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1

Gait Measures and Dynamic Weight bearing in Young and Elder Trans-tibal Amputee using PTB Prosthesis with SACH foot  

Microsoft Academic Search

Objective: to investigate the changes associated with age in gait characteristics and dynamic weight bearing pattern of sound and prosthetic limb of persons with unilateral amputation. Participant: two groups of seven young (24±3.8 years) and seven elderly unilateral amputee (71±6 years) were selected for this study. Setting : both groups walked at their self selected speed over a 20 second

Prasanna K. Lenka; Ratnesh K; D. N. Tibarewala

2

The Effects of Additional Action Observational Training for Functional Electrical Stimulation Treatment on Weight Bearing, Stability and Gait Velocity of Hemiplegic Patients  

PubMed Central

[Purpose] The purpose of this study was to evaluate the functional effects of additional action observational training for functional electrical stimulation treatment on weight bearing, stability and gait velocity of hemiplegic patients. [Subjects and Methods] Twenty subjects were randomized into two groups. Subjects more than six months post-stroke participated. Balance and gait velocity were measured at the baseline, and after six weeks of treatment. Both groups received functional electrical stimulation treatment. The experimental group additionally received action observational training. The paired t-test was used to analyze differences in the outcome measures between before and after the intervention. The difference between the groups was compared using the independent t-test. [Results] The experimental group showed significant increases in weight bearing (anterior·posterior, right·left) on the affected side, stability index and gait velocity. The control group showed only a significant increase in anterior·posterior weight bearing on the affected side. Moreover, according to the comparison of training effects between in the two groups, the variables of anterior·posterior weight bearing, stability index and gait velocity revealed a statistically significant difference. [Conclusion] Additional action observational training for functional electrical stimulation treatment should be considered as a therapeutic method in physical therapy for the improvement of weight bearing, stability index and gait velocity of hemiplegic patients. PMID:24259939

Park, Chang-Sik; Kang, Kwon-Young

2013-01-01

3

The effects of additional action observational training for functional electrical stimulation treatment on weight bearing, stability and gait velocity of hemiplegic patients.  

PubMed

[Purpose] The purpose of this study was to evaluate the functional effects of additional action observational training for functional electrical stimulation treatment on weight bearing, stability and gait velocity of hemiplegic patients. [Subjects and Methods] Twenty subjects were randomized into two groups. Subjects more than six months post-stroke participated. Balance and gait velocity were measured at the baseline, and after six weeks of treatment. Both groups received functional electrical stimulation treatment. The experimental group additionally received action observational training. The paired t-test was used to analyze differences in the outcome measures between before and after the intervention. The difference between the groups was compared using the independent t-test. [Results] The experimental group showed significant increases in weight bearing (anterior·posterior, right·left) on the affected side, stability index and gait velocity. The control group showed only a significant increase in anterior·posterior weight bearing on the affected side. Moreover, according to the comparison of training effects between in the two groups, the variables of anterior·posterior weight bearing, stability index and gait velocity revealed a statistically significant difference. [Conclusion] Additional action observational training for functional electrical stimulation treatment should be considered as a therapeutic method in physical therapy for the improvement of weight bearing, stability index and gait velocity of hemiplegic patients. PMID:24259939

Park, Chang-Sik; Kang, Kwon-Young

2013-09-01

4

Relationship between the weight-bearing ratio on the affected lower extremity and gait ability using a portable electronic foot sensor shoe (Step Aid(®)) in hemiplegic stroke patients.  

PubMed

[Purpose] This study investigated the association between the weight-bearing ratio (WBR) and gait ability of a paretic lower limb while walking using a shoe-type load-measuring apparatus. [Subjects] The Subjects comprised 17 stroke patients who were classified into the following two groups: the independent walking group, and the non-independent walking group. [Methods] The 10-m walking time (inside and outside parallel bars) and the Berg Balance Scale (BBS) were measured. The WBR of the paretic lower limb was measured during static standing and while walking inside and outside parallel bars, and the coefficient of variation (CV) was calculated. WBR was evaluated using the Step Aid. [Results] The BBS and WBR were significantly decreased in the non-independent walking group, while the 10-m walking time and the CV were significantly increased in the non-independent walking group. [Conclusion] The CV and WBR of a paretic lower limb while walking appear to be important indices of achievement of independent gait in hemiplegic stroke patients, and they may be used in gait rehabilitation for diseases requiring weight-bearing training to follow the course of training using a shoe-type load-measuring apparatus. PMID:25729160

Itotani, Keisuke; Murakami, Masahito; Itotani, Motoko; Nagai, Atsushi; Imabori, Yuzo; Fujimoto, Kazuyuki; Tanaka, Mamoru; Kato, Junichi

2015-02-01

5

Relationship between the weight-bearing ratio on the affected lower extremity and gait ability using a portable electronic foot sensor shoe (Step Aid®) in hemiplegic stroke patients  

PubMed Central

[Purpose] This study investigated the association between the weight-bearing ratio (WBR) and gait ability of a paretic lower limb while walking using a shoe-type load-measuring apparatus. [Subjects] The Subjects comprised 17 stroke patients who were classified into the following two groups: the independent walking group, and the non-independent walking group. [Methods] The 10-m walking time (inside and outside parallel bars) and the Berg Balance Scale (BBS) were measured. The WBR of the paretic lower limb was measured during static standing and while walking inside and outside parallel bars, and the coefficient of variation (CV) was calculated. WBR was evaluated using the Step Aid. [Results] The BBS and WBR were significantly decreased in the non-independent walking group, while the 10-m walking time and the CV were significantly increased in the non-independent walking group. [Conclusion] The CV and WBR of a paretic lower limb while walking appear to be important indices of achievement of independent gait in hemiplegic stroke patients, and they may be used in gait rehabilitation for diseases requiring weight-bearing training to follow the course of training using a shoe-type load-measuring apparatus. PMID:25729160

Itotani, Keisuke; Murakami, Masahito; Itotani, Motoko; Nagai, Atsushi; Imabori, Yuzo; Fujimoto, Kazuyuki; Tanaka, Mamoru; Kato, Junichi

2015-01-01

6

Massive weight loss-induced mechanical plasticity in obese gait  

PubMed Central

We examined the hypothesis that metabolic surgery-induced massive weight loss causes mass-driven and behavioral adaptations in the kinematics and kinetics of obese gait. Gait analyses were performed at three time points over ?1 yr in initially morbidly obese (mass: 125.7 kg; body mass index: 43.2 kg/m2) but otherwise healthy adults. Ten obese adults lost 27.1% ± 5.1 (34.0 ± 9.4 kg) weight by the first follow-up at 7.0 mo (±0.7) and 6.5 ± 4.2% (8.2 ± 6.0 kg) more by the second follow-up at 12.8 mo (±0.9), with a total weight loss of 33.6 ± 8.1% (42.2 ± 14.1 kg; P = 0.001). Subjects walked at a self-selected and a standard 1.5 m/s speed at the three time points and were also compared with an age- and gender-matched comparison group at the second follow-up. Weight loss increased swing time, stride length, gait speed, hip range of motion, maximal knee flexion, and ankle plantarflexion. Weight loss of 27% led to 3.9% increase in gait speed. An additional 6.5% weight loss led to an additional 7.3% increase in gait speed. Sagittal plane normalized knee torque increased and absolute ankle and frontal plane knee torques decreased after weight loss. We conclude that large weight loss produced mechanical plasticity by modifying ankle and knee torques and gait behavior. There may be a weight loss threshold of 30 kg limiting changes in gait kinematics. Implications for exercise prescription are also discussed. PMID:21852410

Herring, Cortney; Pories, Walter J.; Rider, Patrick; DeVita, Paul

2011-01-01

7

Secondary motions of the knee during weight bearing and non-weight bearing activities.  

PubMed

The objective of this study was to test the hypothesis that during a weight bearing activity such as walking, a dynamic range (envelope of motion) exists in the relationship between the secondary knee motions (anterior-posterior (AP) translation, internal-external (IE) rotation, and abduction-adduction (Ab-Adduction)) and knee flexion angle. In addition differences in the envelope of motion between a weight bearing and non-weight bearing activity were tested. The hypothesis was evaluated by testing for differences (offsets) in secondary displacements at specific knee flexion angles during the walking cycle and seated leg extension (non-weight bearing). Kinematic measurements were obtained using a previously developed point cluster technique to analyze the six-degrees of freedom movement of the knee. During walking, phase plots of the IE rotation and AP translation versus knee flexion demonstrated significant offsets from one phase of the gait cycle to another at the same flexion angle. During the non-weight bearing activity, no significant offset in the secondary movement was found; the knee followed the same pathway of motion during the flexion and extension phase of this activity. The characteristics of the secondary motions during walking indicated that secondary knee movements are caused by the external forces (muscle, inertial and gravitational) that act on the knee during the various phases of the walking cycle. The boundaries of the envelope appear to reflect the characteristics of the passive restraints. The weight bearing secondary motion AP and IE rotation seen during a walking activity demonstrated an envelope of dynamic laxity that could potentially be used to evaluate functional instabilities at the knee. PMID:15183436

Dyrby, Chris O; Andriacchi, Thomas P

2004-07-01

8

Older adults have unstable gait kinematics during weight transfer.  

PubMed

The present article investigates gait stability of healthy older persons during weight transfer. Ten healthy older persons and ten younger persons walked 10 min each on a treadmill at 3 different gait speeds. The intra-stride change in gait stability was defined by the local divergence exponent ?(t) estimated by a newly developed method. The intra-stride changes in ?(t) during weight transfer were identified by separating each stride into a single and double support phase. The intra-stride changes in ?(t) were also compared to changes in the variation of the gait kinematics, i.e., SD(t). The healthy older persons walked at the same preferred walking speed as the younger persons. However, they exhibited significantly larger ?(t) (p<0.001) during weight transfer in the double support phase. Local divergence was closely related to intra-stride changes in SD(t) of the feet in the anterior-posterior direction. Furthermore, a high correlation was found between local divergence and the variation in step length and step width for both older (R>0.67, p<0.05) and younger persons (R>0.67, p<0.05). The present results indicate that the gait kinematics of older adults are more dynamical unstable during the weight transfer compared to younger persons. Furthermore, a close relationship exists between intra-stride changes in dynamical stability and variation in step length and step width. Further work will validate the results of the present study using real-life perturbations of the gait kinematics of both younger and older adults. PMID:22541943

Ihlen, Espen A F; Sletvold, Olav; Goihl, Tobias; Wik, Per B; Vereijken, Beatrix; Helbostad, Jorunn

2012-06-01

9

Calf stretching in non-weight bearing versus weight bearing.  

PubMed

Limited ankle dorsiflexion passive range of motion (DF PROM) has been associated with lower extremity overuse injuries. Therefore, clinicians often prescribe stretching exercises to increase ankle DF PROM. However, there is limited evidence to indicate if any particular gastrocnemius stretching exercise results in greater improvement in DF PROM. The aim of this study was to determine if gastrocnemius stretching in non-weight bearing (NWB) or weight bearing (WB) results in a greater increase of ankle DF PROM. 28 healthy volunteers, aged 18-55 years, who exhibited less than 10 degrees of ankle DF PROM completed the study. Participants were randomized into 2 stretching groups: NWB and WB. Both groups completed a 3-week home gastrocnemius stretching program, consisting of 5 repetitions held for 30 s each, 2 times daily. Participants' ankle DF PROM was measured with a blinded standard goniometer in NWB and WB positions before and after participation in a 3-week home gastrocnemius stretching program. Two 3-way mixed model ANOVAs demonstrated no significant difference in ankle DF PROM between the NWB and WB groups for either the NWB measurement condition (p=0.49) or WB measurement condition (p=0.86). Gastrocnemius stretching exercises performed in NWB or WB were equally effective in increasing ankle DF PROM. PMID:21181639

Dinh, N V; Freeman, H; Granger, J; Wong, S; Johanson, M

2011-03-01

10

Kinematic and kinetic changes in obese gait in bariatric surgery-induced weight loss.  

PubMed

This study examines the effects of a radical bariatric surgery-induced weight loss on the gait of obese subjects. We performed a three-dimensional motion analysis of lower limbs, and collected force platform data in the gait laboratory to calculate knee and hip joint moments. Subjects (n=13) performed walking trials in the laboratory before and 8.8 months (SD 4.2) after the surgical procedure at two gait speeds (1.2m/s and 1.5m/s). The average weight loss was 26.7kg (SD 9.2kg), corresponding to 21.5% (SD 6.8%) of the initial weight. We observed a decrease in step width at both gait speeds, but no changes in relative double support or swing time or stride length. A significant decrease was noted in the absolute values of peak knee abductor, peak knee flexor and peak hip extensor moments. However, the moment values normalized by the body weight and height remained unchanged in most cases. Thus, we conclude that weight loss reduces hip and knee joint moments in proportion to the amount of weight lost. PMID:22633006

Vartiainen, Paavo; Bragge, Timo; Lyytinen, Tarja; Hakkarainen, Marko; Karjalainen, Pasi A; Arokoski, Jari P

2012-06-26

11

Gait analysis following treadmill training with body weight support versus conventional physical therapy: a prospective randomized controlled single blind study  

Microsoft Academic Search

Study design:Single-blind randomized, controlled clinical study.Objectives:To evaluate, using kinematic gait analysis, the results obtained from gait training on a treadmill with body weight support versus those obtained with conventional gait training and physiotherapy.Setting:Thirty patients with sequelae from traumatic incomplete spinal cord injuries at least 12 months earlier; patients were able to walk and were classified according to motor function as

PR Lucareli; MO Lima; FPS Lima; JG de Almeida; GC Brech; J M D'Andréa Greve

2011-01-01

12

Hip revision with impacted morselized allografts: unrestricted weight-bearing and restricted weight-bearing have similar effect on migration  

Microsoft Academic Search

Background No consensus exists as to whether to let patients bear weight or not after revision of a loosened hip prosthesis using morselized and impacted allograft bone and cement. In the original description of the method, the patients were advised not to bear weight for 3 months postoperatively. Theoretically, bone graft remodeling is enhanced by mechanical load, but an increased migration

Ewald Ornstein; Herbert Franzén; Ragnar Johnsson; Anna Stefánsdóttir; Martin Sundberg; Magnus Tägil

2003-01-01

13

The Combined Effects of Body Weight Support and Gait Speed on Gait Related Muscle Activity: A Comparison between Walking in the Lokomat Exoskeleton and Regular Treadmill Walking  

PubMed Central

Background For the development of specialized training protocols for robot assisted gait training, it is important to understand how the use of exoskeletons alters locomotor task demands, and how the nature and magnitude of these changes depend on training parameters. Therefore, the present study assessed the combined effects of gait speed and body weight support (BWS) on muscle activity, and compared these between treadmill walking and walking in the Lokomat exoskeleton. Methods Ten healthy participants walked on a treadmill and in the Lokomat, with varying levels of BWS (0% and 50% of the participants’ body weight) and gait speed (0.8, 1.8, and 2.8 km/h), while temporal step characteristics and muscle activity from Erector Spinae, Gluteus Medius, Vastus Lateralis, Biceps Femoris, Gastrocnemius Medialis, and Tibialis Anterior muscles were recorded. Results The temporal structure of the stepping pattern was altered when participants walked in the Lokomat or when BWS was provided (i.e. the relative duration of the double support phase was reduced, and the single support phase prolonged), but these differences normalized as gait speed increased. Alternations in muscle activity were characterized by complex interactions between walking conditions and training parameters: Differences between treadmill walking and walking in the exoskeleton were most prominent at low gait speeds, and speed effects were attenuated when BWS was provided. Conclusion Walking in the Lokomat exoskeleton without movement guidance alters the temporal step regulation and the neuromuscular control of walking, although the nature and magnitude of these effects depend on complex interactions with gait speed and BWS. If normative neuromuscular control of gait is targeted during training, it is recommended that very low speeds and high levels of BWS should be avoided when possible. PMID:25226302

Van Kammen, Klaske; Boonstra, Annemarijke; Reinders-Messelink, Heleen; den Otter, Rob

2014-01-01

14

Improvement of gait ability with a short-term intensive gait rehabilitation program using body weight support treadmill training in community dwelling chronic poststroke survivors  

PubMed Central

[Purpose] Most previous studies have shown that body weight support treadmill training (BWSTT) can improve gait speed poststroke patients. The purpose of this study was to evaluate effectiveness of a short-term intensive program using BWSTT among community dwelling poststroke survivors. [Subjects] Eighteen subjects participated in this study. The treatment group was composed of 10 subjects (2 women; 8 men; mean age, 59.1 ± 12.5?years; time since stroke onset, 35.3 ± 33.2 months), whereas the control group was made up of 8 subjects (3 women; 5 men; mean age, 59.8 ± 6.3?years; time since stroke onset, 39.3 ± 27.3 months). [Methods] The treatment group received BWSTT 3 times a week for 4 weeks (a total of 12 times), with each session lasting 20 minutes. The main outcome measures were maximum gait speed on a flat floor, cadence, and step length. [Results] No differences were observed in the baseline clinical data between the 2 groups. The gait speed in the treatment group was significantly improved compared with that in the control by 2-way ANOVA, while the other parameters showed no significant interaction. [Conclusion] These results suggested that short-term intensive gait rehabilitation using BWSTT was useful for improving gait ability among community dwelling poststroke subjects. PMID:25642063

Takao, Toshifumi; Tanaka, Naoki; Iizuka, Noboru; Saitou, Hideyuki; Tamaoka, Akira; Yanagi, Hisako

2015-01-01

15

The role of vision in obese and normal-weight children's gait control.  

PubMed

Previous research has suggested that perceptual-motor difficulties may account for obese children's lower motor competence; however, specific evidence is currently lacking. Therefore, this study examined the effect of altered visual conditions on spatiotemporal and kinematic gait parameters in obese versus normal-weight children. Thirty-two obese and normal-weight children (11.2±1.5 years) walked barefoot on an instrumented walkway at constant self-selected speed during LIGHT and DARK conditions. Three-dimensional motion analysis was performed to calculate spatiotemporal parameters, as well as sagittal trunk segment and lower extremity joint angles at heel-strike and toe-off. Self-selected speed did not significantly differ between groups. In the DARK condition, all participants walked at a significantly slower speed, decreased stride length, and increased stride width. Without normal vision, obese children had a more pronounced increase in relative double support time compared to the normal-weight group, resulting in a significantly greater percentage of the gait cycle spent in stance. Walking in the DARK, both groups showed greater forward tilt of the trunk and restricted hip movement. All participants had increased knee flexion at heel-strike, as well as decreased knee extension and ankle plantarflexion at toe-off in the DARK condition. The removal of normal vision affected obese children's temporal gait pattern to a larger extent than that of normal-weight peers. Results suggest an increased dependency on vision in obese children to control locomotion. Next to the mechanical problem of moving excess mass, a different coupling between perception and action appears to be governing obese children's motor coordination and control. PMID:21094609

D'Hondt, Eva; Segers, Veerle; Deforche, Benedicte; Shultz, Sarah P; Tanghe, Ann; Gentier, Ilse; De Bourdeaudhuij, Ilse; De Clercq, Dirk; Lenoir, Matthieu

2011-02-01

16

Foot Loading Characteristics of Different Graduations of Partial Weight Bearing  

ERIC Educational Resources Information Center

Limited weight bearing of the lower extremity is a commonly applied procedure in orthopaedic rehabilitation after reconstructive forefoot surgery, trauma surgery and joint replacement. The most frequent limitations are given as percentage of body weight (BW) and represent 10 or 50% BW. The extent of foot loading under these graduations of partial…

Gusinde, Johannes; Pauser, Johannes; Swoboda, Bernd; Gelse, Kolja; Carl, Hans-Dieter

2011-01-01

17

Reconstructing weight-bearing surfaces: digital pad transposition.  

PubMed

The paw pads of dogs and cats are specialized skin structures that provide cushioned, durable, weight-bearing surfaces. Otherwise normal limbs may be rendered useless when pad tissue is lost because of trauma or tumor resection. This article reviews previously described reconstructive techniques involving the movement of pad tissue into weight-bearing defects. In addition, a case series of single-stage digital pad transfer to replace all or part of metacarpal or metatarsal defects is reported. This technique was predictably successful with minimal complications in conjunction with complete tumor resection, although results in two cases of severe paw trauma were less favorable. PMID:17724941

Neat, Benjamin C; Smeak, Daniel D

2007-01-01

18

Weights and hematology of wild black bears during hibernation  

USGS Publications Warehouse

We compared weights and hematological profiles of adult (greater than 3-yr-old) female black bears (Ursus americanus) during hibernation (after 8 January). We handled 28 bears one to four times (total of 47) over 4 yr of varying mast and berry production. Mean weight of lactating bears was greater (P less than 0.0001) than that of non-lactating females. White blood cells (P less than 0.05) and mean corpuscular volume (P = 0.005) also differed between lactating and non-lactating bears. Hemoglobin (P = 0.006) and mean corpuscular hemoglobin concentration (P = 0.02) varied among years; values were lowest during 1975, following decreased precipitation and the occurrence of a second year of mast and berry crop shortages in a three-year period. Significant (P less than 0.05) interaction between reproductive status (lactating versus non-lactating) and study year for hemoglobin, red blood cells, and packed cell volume, and increased mean corpuscular volume, suggested a greater nutritional challenge for lactating females compared to non-lactating females during the 1975 denning season. Our data suggest that hematological characteristics of denning bears may be more sensitive than weights as indicators of annual changes in nutritional status; however, other influential factors, in addition to mast and berry crop production, remain to be examined.

DelGiudice, Glenn D.; Rogers, Lynn L.; Allen, Arthur W.; Seal, U.S.

1991-01-01

19

The use of body weight support on ground level: an alternative strategy for gait training of individuals with stroke  

Microsoft Academic Search

BACKGROUND: Body weight support (BWS) systems on treadmill have been proposed as a strategy for gait training of subjects with stroke. Considering that ground level is the most common locomotion surface and that there is little information about individuals with stroke walking with BWS on ground level, it is important to investigate the use of BWS on ground level in

Catarina O Sousa; José A Barela; Christiane L Prado-Medeiros; Tania F Salvini; Ana MF Barela

2009-01-01

20

Determinants of bone density among athletes engaged in weight-bearing and non-weight-bearing activity  

NASA Technical Reports Server (NTRS)

The effect of weight bearing activity on the bone density was investigated in athletes by comparing the measures of bone density of athletes engaged in weight-training programs with those of polo players and nonexercising subjects. All subjects had measurements of spinal trabecular and integral bone density by quantitative tomography, as well as determinations of hip bone density by dual photon absorptiometry. Results confirmed previous findings by Block et al. (1987) of significantly greater bone density among highly trained athletes compared with nonexercising subjects of similar age. Results also indicated that athletes engaged in non-weight-bearing forms of rigorous exercise had greater levels of bone density. However, as the participants in this study were exceptional athletes, engaged in a strenuous sport with both aerobic and heavy resistance components, a confirmation of these data is needed, using larger samples of individuals.

Block, Jon E.; Friedlander, Anne L.; Brooks, George A.; Steiger, Peter; Stubbs, Harrison A.

1989-01-01

21

Using Gait as a Biometric, via Phase-weighted Magnitude Spectra  

Microsoft Academic Search

Abstract. Gait is a ,biometric which ,is subject ,to increasing ,interest. Current approaches,include modelling ,gait as a ,spatio-temporal sequence ,and ,as an articulated model. By considering legs only, gait can be considered to be the motion,of interlinked pendula. We describe how,the Hough transform is used to extract the lines which represent legs in sequences,of video,images. The change in inclination of

David Cunado; Mark S. Nixon; John N. Carter

1997-01-01

22

Immediate Weight-Bearing after Ankle Fracture Fixation  

PubMed Central

We believe that a certain subset of surgical ankle fracture patients can be made weight-bearing as tolerated immediately following surgery. Immediate weight-bearing as tolerated (IWBAT) allows patients to return to ambulation and activities of daily living faster and may facilitate rehabilitation. A prospectively gathered orthopaedic trauma database at a Level 1 trauma center was reviewed retrospectively to identify patients who had ORIF after unstable ankle injuries treated by the senior author. Patients were excluded if they were not IWBAT based on specific criteria or if they did meet followup requirement. Only 1/26 patients was noted to have loss of fixation. This was found at the 6-week followup and was attributed to a missed syndesmotic injury. At 2-week followup, 2 patients had peri-incisional erythema that resolved with a short course of oral antibiotics. At 6-week followup, 20 patients were wearing normal shoes and 6 patients continued to wear the CAM Boot for comfort. To conclude, IWBAT in a certain subset of patients with stable osteosynthesis following an ankle fracture could potentially be a safe alternative to a period of protected weight-bearing. PMID:25785201

Harnden, Emily

2015-01-01

23

Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy  

NASA Technical Reports Server (NTRS)

This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

1992-01-01

24

Effects of weight bearing and non-weight bearing exercises on bone properties using calcaneal quantitative ultrasound  

PubMed Central

Objective: This study was designed to investigate bone properties using heel quantitative ultrasound (QUS) in young adults participating in various sports. Methods: A cross sectional study was performed on Chinese male students (n = 55), aged 18–22 years. Subjects with previous fractures or suffering from any diseases known to affect bone metabolism or taking any medication with such an effect, were not included. The subjects were categorised according to their main sporting activities, including soccer (n = 15) (a high impact, weight bearing exercise), dancing (n = 10) (a low impact, weight bearing exercise), and swimming (n = 15) (non-weight bearing exercise). A sedentary group acted as controls (n = 15). A reproducibility study of the velocity of sound (VOS) and the broadband ultrasound attenuation (BUA) measurement was performed and analysed using the intraclass correlation coefficient (ICC). Results: There was good intra-investigator and inter-investigator agreement (ICC?0.8; p<0.05) in the measurement of BUA and VOS. No significant differences in BUA and VOS (p>0.05) were found between the dominant and non-dominant heel. Soccer players (137±4.3 dB/MHz; 1575±56 m/s; 544.1±48.4) and dancers (134.6±3.7 dB/MHz; 1538±46 m/s; 503.0±37.0) had significantly higher BUA, VOS, and stiffness index (SI) scores (p<0.05), respectively, than swimmers (124.1±5.1 dB/MHz; 1495±42 m/s; 423.3±46.9) and the sedentary control group (119.9±6.1 dB/MHz; 1452±41 m/s; 369.9±46.4). A trend of a significant linear increase with the weight bearing and high impact exercise was revealed in all QUS parameters (p<0.05). Conclusion: This cross sectional study indicated that regular participation in weight bearing exercise in young people might be beneficial for accruing peak bone mass and optimising bone structure. PMID:16046341

Yung, P; Lai, Y; Tung, P; Tsui, H; Wong, C; Hung, V; Qin, L

2005-01-01

25

Effects of Weight Bearing Intervals on Disuse Atrophy of Rat Soleus Muscle  

PubMed Central

The purpose of this study was to investigate the effects of weight bearing at varying intervals in suppressing the progression of disuse muscle atrophy, while setting the total daily weight bearing time constant. Disuse muscle atrophy was induced by 2-week hindlimb suspension. Thirty male Wistar rats ( weight : 215 ± 8 g ) were divided into 6 groups ( 5 rats/group ) : control (CON), suspension alone (SUS), two sessions of 30-minute weight bearing at intervals of 4, 8, and 12 hours during suspension, and one session of 60-minute weight bearing at intervals of 24 hours during suspension. Weight bearing was done each day during the daytime. Histochemical staining, followed by morphometrical analysis using NIH Image, demonstrated that the cross-sectional area of type I fiber in SUS was 44% of that in CON, while in the weight bearing groups ranged from 62 to 70%. The proportion of type I fibers was lower in SUS and tended to increase as the interval of weight bearing become longer, indicating the effects of weight bearing at intervals of 12 and 24 hours. For both types I and II, the distribution of muscle fiber size indicated that weight bearing at longer intervals was more effective in keeping the cross-sectional areas of muscle fibers closed to that in CON. In conclusion, when suppressing the progression of disuse atrophy of rat soleus muscle by weight bearing of one hour per day, the results suggest that the weight bearing intervals is important factor.

Haida, Nobuhide; Tachino, Katsuhiko

1998-01-01

26

Method for estimating maximum permissible load weight for Japanese native horses using accelerometer-based gait analysis.  

PubMed

The aim of this study was to establish a method for estimating loading capacity for Japanese native horses by gait analysis using an accelerometer. Six mares of Japanese native horses were used. The acceleration of each horse was recorded during walking and trotting along a straight course at a sampling frequency of 200?Hz. Each horse performed 12 tests: one test with a loaded weight of 80?kg (First 80?kg) followed by 10 tests with random loaded weights between 85?kg and 130?kg and a final test with a loaded weight of 80?kg again. The time series of acceleration was subjected to fast Fourier transformation, and the autocorrelation coefficient was calculated. The first two peaks of the autocorrelation were defined as symmetry and regularity of the gait. At trot, symmetries in the 100, 110, and 125?kg tests were significantly lower than that in First 80?kg (P?weight is less than 100?kg, which is 29% of the body weight of Japanese native horses. Our method is a widely applicable and welfare-friendly method for estimating maximum permissible load weights of horses. PMID:23302086

Matsuura, Akihiro; Irimajiri, Mami; Matsuzaki, Kunihiro; Hiraguri, Yuko; Nakanowatari, Toshihiko; Yamazaki, Atusi; Hodate, Koichi

2013-01-01

27

[Management of weight-bearing area fracture of acetabulum].  

PubMed

Acetabulum, as the important factor for weight bearing of the upper body, has its unique anatomic features and complicated physiological function. The integrity and stability of the lunata articular surface in the dome region of acetabulum, is the important base to bear the physiological function of acetabulum. The fracture related to this part will cause relation change of contact area and stress between head of femur and acetabulum. Furthermore, the deep anatomical position of the dome region, the complicated surrounding anatomical relation, and the irregular bony structure will also increase the difficulty of surgical treatment. Especially for some complicated comminuted or compressed fracture, even with good explosions, it is hard to get satisfied anatomical reduction. Consequently,forward traumatic arthritis has greater probability of occurrence. Therefore, the clinical research on the fracture in the dome region of acetabulum was getting more and more attention worldly. This paper intended to review the relation of fracture classifications and anatomic features, physiological function,diagnostic criteria,and also its clinical treating countermeasure. PMID:21438324

Zhang, Yun-tong; Wang, Pan-feng; Zhang, Chun-cai

2011-02-01

28

Changes in skeletal muscle gene expression consequent to altered weight bearing  

NASA Technical Reports Server (NTRS)

Skeletal muscle is a dynamic organ that adapts to alterations in weight bearing. This brief review examines changes in muscle gene expression resulting from the removal of weight bearing by hindlimb suspension and from increased weight bearing due to eccentric exercise. Acute (less than or equal to 2 days) non-weight bearing of adult rat soleus muscle alters only the translational control of muscle gene expression, while chronic (greater than or equal to 7 days) removal of weight bearing appears to influence pretranslational, translational, and posttranslational mechanisms of control. Acute and chronic eccentric exercise are associated with alterations of translational and posttranslational control, while chronic eccentric training also alters the pretranslational control of muscle gene expression. Thus alterations in weight bearing influence multiple sites of gene regulation.

Booth, F. W.; Kirby, C. R.

1992-01-01

29

Influence of Hindlimb Unweighting and Intermittent Weight Bearing on Dynamics of Nuclei in Rat Soleus Muscle  

PubMed Central

The purpose of this study was to examine differences in the inhibitory effect of disuse atrophy as a result of intermittent weight bearing in terms of the dynamics of nuclei in rat soleus muscle. Disuse muscle atrophy was induced by hindlimb suspension for two weeks. Forty-nine male Wistar rats (body weight: 190–228 g) were divided into the control group (CON) and the experimental group. The experimental group was subdivided into four groups: hindlimb suspension alone (HS), weight bearing for 10 minutes × 4 times/day (W10), weight bearing for 20 minutes × 2 times/day (W20), and weight bearing for 40 minutes × one time/day (W40). In addition to histochemical examination, this study examined both cell proliferation and apoptosis in terms of the dynamics of myonuclei immuno-histochemically. The mean cross-sectional area of muscle fibers demonstrated the effect of weight bearing. The number of proliferating myonuclei per 100 muscle fibers was decreased in the experimental groups as compared with CON. Proliferating myonuclei in W10 and W40 were more than HS, indicating the effect of weight bearing. Apoptotic myonuclei was increased in the experimental groups as compared with CON. This parameter in W10 and W40 were statistically not significantly different from CON, suggesting that these weight bearing methods can prevent the loss of myonuclei by apoptosis. However, W20 was not significantly different from HS in terms of the dynamics of myonuclei. This suggests that weight bearing for W20 was ineffective. The results in this study indicated the possibility of inducing different effects by the frequency of weight bearing.

2003-01-01

30

Kinematic Analysis of Healthy Hips during Weight-Bearing Activities by 3D-to-2D Model-to-Image Registration Technique  

PubMed Central

Dynamic hip kinematics during weight-bearing activities were analyzed for six healthy subjects. Continuous X-ray images of gait, chair-rising, squatting, and twisting were taken using a flat panel X-ray detector. Digitally reconstructed radiographic images were used for 3D-to-2D model-to-image registration technique. The root-mean-square errors associated with tracking the pelvis and femur were less than 0.3?mm and 0.3° for translations and rotations. For gait, chair-rising, and squatting, the maximum hip flexion angles averaged 29.6°, 81.3°, and 102.4°, respectively. The pelvis was tilted anteriorly around 4.4° on average during full gait cycle. For chair-rising and squatting, the maximum absolute value of anterior/posterior pelvic tilt averaged 12.4°/11.7° and 10.7°/10.8°, respectively. Hip flexion peaked on the way of movement due to further anterior pelvic tilt during both chair-rising and squatting. For twisting, the maximum absolute value of hip internal/external rotation averaged 29.2°/30.7°. This study revealed activity dependent kinematics of healthy hip joints with coordinated pelvic and femoral dynamic movements. Kinematics' data during activities of daily living may provide important insight as to the evaluating kinematics of pathological and reconstructed hips. PMID:25506056

Hara, Daisuke; Nakashima, Yasuharu; Hamai, Satoshi; Higaki, Hidehiko; Ikebe, Satoru; Shimoto, Takeshi; Hirata, Masanobu; Kanazawa, Masayuki; Kohno, Yusuke; Iwamoto, Yukihide

2014-01-01

31

Correlation of psychomotor findings and the ability to partially weight bear  

PubMed Central

Background Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test. Methods 50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS). To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction. Results The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously. Conclusions The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits. PMID:22330655

2012-01-01

32

Weight bearing and velocity in trans-tibial and trans-femoral amputees  

Microsoft Academic Search

The purpose of this study was to review the clinical utility of static weight bearing (SWB) and maximal self-selected ambulatory velocity as objective quantifiable measures in an outpatient lower limb prosthetic clinic. Seventy-three (n=73) consecutive trans-tibial (TTA) and trans-femoral amputees (TFA) attending an outpatient prosthetic clinic were studied. Prosthetic weight bearing was measured on a bathroom scale (mass in kg),

M. E. JONES; G. M. BASHFORD; J. M. MANN

33

Patellofemoral joint contact area increases with knee flexion and weight-bearing  

E-print Network

Patellofemoral joint contact area increases with knee flexion and weight-bearing Thor F. Besier a° from vertical with the knee positioned at 0°, 30°, or 60° of flexion. A custom-built backrest enabled) and reduced loading con- ditions (ÔunloadedÕ at 0.15 body weight) at each knee flexion posture. Male subjects

Stanford University

34

Early full weight bearing is safe in open-wedge high tibial osteotomy  

PubMed Central

Background and purpose In open-wedge, valgus osteotomy of the upper tibia, there are concerns regarding the initial stability and ability to retain the correction. Rehabilitation protocols vary depending on the osteotomy technique and the fixation method. Angle-stable implants offer superior initial stability. Early full weight bearing appears to be possible using these implants. In this prospective cohort study, we measured migration in open-wedge osteotomy in patients following an early full weight bearing protocol and compared the results to those from a historical cohort of open-wedge osteotomy patients who followed a standard protocol (full weight bearing after 6 weeks) using radiostereometry. Methods 14 open-wedge osteotomies fixated with the angle-stable Tomofix implant were performed; patients were allowed full weight bearing as soon as pain and wound healing permitted. Radiostereometry was used to measure motion across the osteotomy at regular intervals. Improvement in pain and functional outcome were assessed postoperatively. The results were compared to those from a group of 23 patients who had undergone the same operation but had used a standard rehabilitation protocol. Results There were no adverse effects because of the early full weight bearing protocol. There were no differences in motion at the osteotomy between groups as measured by radiostereometry. In both groups, pain and function improved substantially without any differences between groups. Patients in the early weight bearing group achieved the same result but in a shorter time. Interpretation Tomofix-plate-fixated open-wedge high tibial osteotomy allows early full weight bearing without loss of correction. PMID:20175658

Brinkman, Justus-Martijn; Luites, Joan WH; Wymenga, Ate B

2010-01-01

35

Improvements in gait speed and weight shift of persons with traumatic brain injury and vestibular dysfunction using a virtual reality computer-assisted rehabilitation environment.  

PubMed

Many people sustaining a traumatic brain injury experience vestibular pathology requiring physical therapy for treatment. This study measured improvements in gait speed and weight shift for subjects receiving vestibular physical therapy using a Computer-Assisted Rehabilitation Environment (CAREN). A 6-session CAREN, 6-session traditional vestibular therapy group was compared with a 12-session CAREN only (0 traditional sessions) therapy group. These two groups were compared to each other and with data from healthy controls performing similar tasks on the CAREN. Those participating in 12 CAREN sessions had greater improvements in gait speed (p = 0.014) and weight shift scores (p < 0.001) and demonstrated similar values achieved by a healthy control population. PMID:25747645

Sessoms, Pinata H; Gottshall, Kim R; Collins, John-David; Markham, Amanda E; Service, Kathrine A; Reini, Seth A

2015-03-01

36

Bears  

NSDL National Science Digital Library

What are the characteristics of grizzly/brown bears and black bears? As you view the websites, please use this chart to record what you are learning about grizzly bears and black bears. For each bear, you should list 5 characteristics. Grizzly Bear and Black Bear Chart We will first begin by learning about black bears. Please go to these websites to learn some important facts about black bears. Black Bears Facts and Image Black Bear Facts for Kids Now that you have learned ...

Miss Bledsoe

2011-04-07

37

Neural network analysis of gait biomechanical data for classification of knee osteoarthritis  

Microsoft Academic Search

Osteoarthritis is a degenerative joint disease, which causes the degradation of articular cartilage and subchondral bone. The disease may result in mechanical abnormalities of the joints, including weight bearing joints such as the knees and hips. In this work, we analyze gait biomechanical data using neural network models to predict the level of joint deterioration and the level of pain

J. McBride; S. Zhang; M. Wortley; M. Paquette; G. Klipple; E. Byrd; L. Baumgartner; X. Zhao

2011-01-01

38

Short communication: Estimation of genetic parameters for gait in Canadian Holstein cows.  

PubMed

Lameness is one of the most important welfare and economic problems in modern dairy herds. In addition to environmental factors, lameness is affected by genetics and thus, long-term improvement of lameness can be accomplished through genetic selection. The objective of the study was to estimate the genetic parameters of a validated gait score and specific gait attributes for Holstein cows from a university dairy research herd. Two hundred thirty-three cows were gait scored multiple times over time (n=1,664 records) in different experiments using a 1-to-5 numerical rating system (NRS). One hundred seventy-two cows (n=657 records) also had 6 gait attributes scored using a 100-unit continuous visual analog scale (back arch, head bob, tracking up, joint flexion, asymmetric gait, and reluctance to bear weight). Single-trait linear animal models were used to estimate the heritability of NRS and each gait attribute, whereas a multivariate linear animal model was used to estimate genetic correlations between traits. The NRS and the gait attributes deteriorated with parity, and the scores for NRS, back arch, joint flexion, and asymmetry of the steps increased rapidly in early lactation. The heritability estimate (±SE) for NRS was 0.09±0.09. Four of the gait attributes (reluctance to bear weight, head bob, tracking up, and asymmetry of the steps) had higher heritability than NRS, ranging from 0.11±0.13 to 0.42±0.15, whereas back arch showed no genetic variation. However, the small sample of animals resulted in large standard error of the estimates. The genetic correlations between NRS and the gait attributes were >0.70, whereas the genetic correlations among the different gait attributes ranged from 0.14 to 0.92. In conclusion, NRS and most gait attributes showed genetic variation, indicating the opportunity to improve gait through genetic selection. Some specific gait attributes were more heritable than NRS and were genetically correlated with NRS. Further research with a larger population is needed to assess whether specific gait attributes would be suitable candidate traits to consider in genetic evaluations in the future. PMID:23063149

Chapinal, N; Sewalem, A; Miglior, F

2012-12-01

39

Osteoporosis Knowledge, Calcium Intake, and Weight-Bearing Physical Activity in Three Age Groups of Women.  

ERIC Educational Resources Information Center

Determined the extent and integration of osteoporosis knowledge in three age groups of women, comparing knowledge to calcium intake and weight bearing physical activity (WBPA). Overall calcium intake was relatively high. There were no differences in knowledge, calcium intake, or WBPA by age, nor did knowledge predict calcium intake and WBPA. None…

Terrio, Kate; Auld, Garry W.

2002-01-01

40

A Newly Designed Postoperative Ischial Weight-Bearing Proximal Contact Lower-Limb Prosthesis  

Microsoft Academic Search

Postamputation prostheses for the lower extremities help reduce medical complications and improve patients overall function. However, there were drawbacks with these postoperative prostheses that limited their use. A recent development is a newly designed ischial weight-bearing prosthesis used postoperatively. We performed a random review of 12 amputee patients retrospectively to determine whether there were any complications with its use. There

Daniel M. Ryan

1998-01-01

41

Surface texture and micromechanics of ultra high molecular weight polyethylene (UHMWPE) orthopaedic implant bearings  

NASA Astrophysics Data System (ADS)

Tibial bearings of ultra-high molecular weight polyethylene (UHMWPE) were characterized to identify differences in morphology, surface texture (roughness and skewness), and micro-scale mechanical behavior. These orthopaedic implant components were fabricated by direct molding or by machining after isostatic compression molding. Sterilization was by gamma irradiation (3.3 Mrad) in air, followed by shelf aging for 2 years. Comparisons were made between unsterile and sterile bearings to identify differences in structure and properties related to wear debris. Characterization methods included confocal optical microscopy, nanoindentation, small angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and polarized light microscopy. Morphology was compared between bulk and surface (top and bottom) specimens of the bearings. Cryo-microtomy was used to prepare thin specimens transverse to the top surface for polarized microscopy. Nanoindentation was performed on the top bearing surfaces, near areas examined by confocal microscopy. Processing methods affected both small- and large-scale morphology of UHMWPE. Direct molding produced thinner lamellae, thicker long periods, and slightly lower crystallinity than isostatic compression molding. Both bearing types contained a thick interface between the crystalline and amorphous phases. Interfacial free energy varied with interface thickness. Resin particles were consolidated better in direct molded bearings than in machined bearings. Segregated amorphous regions were observed in the machined bearings. Sterilization and shelf aging affected nanometer-scale morphology. Chain scission significantly decreased the interface thickness, causing an increase in lamellar thickness and a small increase in crystallinity. Only a small decrease in the amorphous thickness resulted. Heterogeneous oxidation increased these changes in interface thickness and lamellar thickness at the surfaces. Thin lamellae were created in the direct molded bearing, uniformly through its thickness, following chain scission and crystallization at low temperature. Both surface roughness and morphology affected micromechanical behavior by nanoindentation. Indents must extend deeper than the peak-to-valley height (2--11 mum) of surface features, near the scale of wear debris. Hardness and elastic modulus correlated with lamellar thickness. Machined bearings were harder and stiffer than direct molded bearings. Sterilization increased lamellar thickness, so properties of the sterile, molded bearing approached those of the unsterile, machined bearing.

Schmidt, Monica A.

2001-07-01

42

Walking assistance apparatus using a spatial parallel link mechanism and a weight bearing lift.  

PubMed

A prototype for a walking assistance apparatus for the elderly or motor palsy patients was developed as a next-generation vehicle or movable neuro-rehabilitation training appliance, using a novel spatial parallel link mechanism and a bearing lift. The flat steps of the apparatus move in parallel with the ground; the apparatus can support entire leg alignment (including soles) and assist; walking behavior at ankle, knee and hip joints simultaneously. In order to respond the variation of equipped person's walking velocity, the length of stride and walking cycle while walking with wearing the apparatus were compensated by using the relation of walking ratio. Therefore the apparatus can be controlled in response to equipped person's will. Motor palsy and muscle weakness patients can walk by themselves by using the apparatus; patients who have ambulation difficulty can use the apparatus with weight bearing lift that we developed. Using the apparatus with the weight bearing lift prevents stumbling and enables input of walking movement to the brain motor area. It is very effective for rehabilitation to use the apparatus with the weight bearing lift. This newly developed system facilitates motor palsy and muscle weakness patients in the rehabilitation program. PMID:22275667

Tanaka, Eiichirou; Ikehara, Tadaaki; Sato, Yusuke; Yusa, Hirokazu; Sakurai, Tomohiro; Saegusa, Shozo; Ito, Kazuhisa; Yuge, Louis

2011-01-01

43

The impact of adding weight-bearing exercise versus nonweight bearing programs to the medical treatment of elderly patients with osteoporosis  

PubMed Central

Background: Osteoporosis is a major public health problem affecting the elderly population, particularly women. The objective of the study was to evaluate the effects of adding weight-bearing exercise as opposed to nonweight-bearing programs to the medical treatment of bone mineral density (BMD) and health-related quality of life (HRQoL) of elderly patients with osteoporosis. Materials and Methods: Participating in the study were 40 elderly osteoporotic patients (27 females and 13 males), with ages ranging from 60 to 67 years, who were receiving medical treatment for osteoporosis. They were assigned randomly into two groups: Group-I: Twenty patients practiced weight-bearing exercises. Group-II: Twenty patients did nonweight-bearing exercises. All patients trained for 45-60 min/session, two sessions/week for 6 months. BMD of the lumbar spine, right neck of femur, and right distal radial head of all patients were measured by dual-energy X-ray absorptiometry before and after both treatment programs. In addition, the QoL was measured by means of the HRQoL “ECOS-16” questionnaire. Results: T-tests proved that mean values of BMD of the lumbar spine, right neck of femur and right distal radial head were significantly increased in both groups with greater improvement in the weight-bearing group. The QoL was significantly improved in both groups, but the difference between them was not significant. Conclusion: Addition of weight-bearing exercise program to medical treatment increases BMD more than nonweight-bearing exercise in elderly subjects with osteoporosis. Furthermore, both weight-bearing and nonweight-bearing exercise programs significantly improved the QoL of patients with osteoporosis. PMID:25374469

Shanb, Alsayed A.; Youssef, Enas F.

2014-01-01

44

Static versus dynamic prosthetic weight bearing in elderly trans-tibial amputees  

Microsoft Academic Search

The purpose of this study was to compare prosthetic weight-bearing tolerance in the standing position to the dynamic vertical ground reaction forces (VGRF) experienced during walking in elderly dysvascular trans-tibial amputees. Ten unilateral trans-tibial amputees attending an amputee clinic (mean age =67±6.5 years) were selected as subjects. Selection criteria were the level of amputation, age, medical fitness to participate and

M. E. JONES; J. R. STEEL; G. M. BASHFORD; I. R. DAVIDSON

1997-01-01

45

Patient compliance with postoperative lower extremity touch-down weight-bearing orders at a level I academic trauma center.  

PubMed

After lower extremity fracture or surgery, physicians often prescribe limited weight bearing. The current study was performed to evaluate teaching and compliance of touch-down weight bearing (defined as 25 lb) at a level I academic trauma center. A survey was distributed to physical therapists (PTs) from the orthopedic ward to gauge their training methods and their confidence in patients' ability to comply. Patients with recommended touch-down weight bearing were then evaluated on the day of discharge and again at their first follow-up appointment using the SmartStep weight-bearing measurement device (Andante Medical Devices, Inc, White Plains, New York). Fifteen PTs completed the survey (average of 14 years in practice). Inconsistency was observed in weight-bearing teaching methods: verbal cues were used 87% of the time, tactile methods were used 41%, demonstration was used 23%, and a scale was used only 1%. Limited confidence was found in the instruction efficacy by those surveyed. Twenty-one patients were seen the day of discharge and 18 of those were seen at first follow-up. At discharge, average minimum and maximum weight bearing were 3.2 and 30.2 lb, respectively. Only 31% of steps were within an acceptable range of 15 to 35 lb. At first follow-up, average minimum and maximum weight bearing were 12.2 and 50.8 lb, respectively. Only 27% of steps were within the acceptable range. The majority of steps were less than the prescribed weight at discharge, whereas the majority of steps were greater than the prescribed weight at first follow-up. These data suggest that more uniform and effective teaching methods for prescribed weight-bearing orders are warranted assuming compliance is an important clinical objective. PMID:24972436

Ruiz, Ferrin K; Fu, Michael C; Bohl, Daniel D; Hustedt, Joshua W; Baumgaertner, Michael R; Leslie, Michael P; Grauer, Jonathan N

2014-06-01

46

Weight-Bearing Versus Nonweight-Bearing Exercise for Persons With Diabetes and Peripheral Neuropathy: A Randomized Controlled Trial  

PubMed Central

Objective To determine the effects of weight-bearing (WB) versus nonweight-bearing (NWB) exercise for persons with diabetes mellitus (DM) and peripheral neuropathy (PN). Design Randomized controlled trial with evaluations at baseline and after intervention. Setting University-based physical therapy research clinic. Participants Participants with DM and PN (N=29) (mean age ± SD, 64.5±12.5y; mean body mass index [kg/m2] ± SD, 35.5±7.3) were randomly assigned to WB (n=15) and NWB (n=14) exercise groups. All participants (100%) completed the intervention and follow-up evaluations. Interventions Group-specific progressive balance, flexibility, strengthening, and aerobic exercise conducted sitting or lying (NWB) or standing and walking (WB) occurred 3 times a week for 12 weeks. Main Outcome Measures Measures included the 6-minute walk distance (6MWD) and daily step counts. Secondary outcome measures represented domains across the International Classification of Functioning, Disability and Health. Results The WB group showed greater gains than the NWB group over time on the 6MWD and average daily step count (P<.05). The mean and 95% confidence intervals (CIs) between-group difference over time was 29m (95% CI, 6–51) for the 6MWD and 1178 (95% CI, 150–2205) steps for the average daily step count. The NWB group showed greater improvements than the WB group over time in hemoglobin A1c values (P<.05). Conclusions The results of this study indicate the ability of this population with chronic disease to increase 6MWD and daily step count with a WB exercise program compared with an NWB exercise program. PMID:23276801

Mueller, Michael J.; Tuttle, Lori J.; LeMaster, Joseph W.; Strube, Michael J; McGill, Janet B.; Hastings, Mary K.; Sinacore, David R.

2013-01-01

47

Joint stabilisers or moment actuators: the role of knee joint muscles while weight-bearing.  

PubMed

Previous investigations have identified the roles of knee joint muscles in supporting external loads during non-weight-bearing tasks and found these to depend on moment arm orientation (MAO). However, during weight-bearing tasks ground reaction forces (GRF) are transferred up through the knee, subjecting it to large multi-directional forces and stability is dependent on articular geometry, loading, and muscle activation. The purpose of this study was to investigate activation strategies used by healthy individuals to generate and support highly controlled GRF during weight-bearing. Twenty healthy males (23.9±1.9 yrs) stood with their foot in a boot fixed to a force platform. Subjects controlled an onscreen cursor by modulating normalised GRF and were required to produce 30% of their maximal force in 12 directions of the horizontal plane while maintaining 50% body weight on the test leg. Lower limb electromyography, kinematics and kinetics were recorded for each trial. Mean muscle activation was plotted in polar coordinates based on GRF orientation. Muscle activation symmetry was determined and when applicable, the mean direction of activation and muscle specificity index reported. The measured GRF were comparable to activities of daily living (0.48-0.58±0.17-0.19 N/kg in horizontal plane). Muscle activations were repeatable (ICCs: 0.78-0.98), however, only semitendinosus (ST) activation was indicated by its MAO. Considering the joint moments and activations patterns we therefore classified muscles as: (1) general joint stabilisers (vastus lateralis and medialis), (2) specific joint stabiliser (BF), and (3) moment actuators (ST and rectus femoris). General joint stabilisers were active in all load directions; specific stabilisers were active in directions opposite their MAO; moment actuators had higher specificities and activations corresponding to their MAO. We suggest the stabiliser muscles create a rigid mechanical linkage at the knee which allows the actuators of the hip and knee to modulate GRF. PMID:22947435

Flaxman, Teresa E; Speirs, Andrew D; Benoit, Daniel L

2012-10-11

48

Balzac and human gait analysis.  

PubMed

INTRODUCTION: People have been interested in movement analysis in general, and gait analysis in particular, since ancient times. Aristotle, Hippocrates, Galen, Leonardo da Vinci and Honoré de Balzac all used observation to analyse the gait of human beings. The purpose of this study is to compare Honoré de Balzac's writings with a scientific analysis of human gait. SOURCES: Honoré de Balzac's Theory of walking and other works by that author referring to gait. DEVELOPMENT: Honoré de Balzac had an interest in gait analysis, as demonstrated by his descriptions of characters which often include references to their way of walking. He also wrote a treatise entitled Theory of walking (Théorie de la demarche) in which he employed his keen observation skills to define gait using a literary style. He stated that the walking process is divided into phases and listed the factors that influence gait, such as personality, mood, height, weight, profession and social class, and also provided a description of the correct way of walking. CONCLUSIONS: Balzac considered gait analysis to be very important and this is reflected in both his character descriptions and Theory of walking, his analytical observation of gait. In our own technology-dominated times, this serves as a reminder of the importance of observation. PMID:22658456

Collado-Vázquez, S; Carrillo, J M

2012-05-31

49

Orthotic devices and gait in polio patients.  

PubMed

Polio survivors are aging and facing multiple pathologies. With age, walking becomes more difficult, partly due to locomotor deficits but also as a result of weight gain, osteoarticular degeneration, pain, cardiorespiratory problems or even post polio syndrome (PPS). These additional complications increase the risk of falls in this population where the risk of fractures is already quite high. The key joint is the knee. The muscles stabilizing this joint are often weak and patients develop compensatory gait strategies, which could be harmful to the locomotor system at medium or long term. Classically, knee recurvatum is used to lock the knee during weight bearing; however, if it exceeds 10 degrees , the knee becomes unstable and walking is unsafe. Thus, regular medical monitoring is necessary. Orthoses play an important role in the therapeutic care of polio survivors. The aim is usually to secure the knee, preventing excessive recurvatum while respecting the patient's own gait. Orthoses must be light and pressure-free if they are to be tolerated and therefore effective. Other joints present fewer problems and orthoses are rarely indicated just for them. The main issue lies in the prior evaluation of treatments' impact. Some deformities may be helpful for the patients' gait and, therefore, corrections may worsen their gait, especially if a realignment of segments is attempted. It is therefore essential to carefully pre-assess any change brought to the orthoses as well as proper indications for corrective surgery. In addition, it is essential for the patient to be monitored by a specialized team. PMID:20022835

Genêt, F; Schnitzler, A; Mathieu, S; Autret, K; Théfenne, L; Dizien, O; Maldjian, A

2010-02-01

50

Range of motion after total knee arthroplasty The effect of implant design and weight-bearing conditions  

Microsoft Academic Search

Knee range of motion was determined in 60 patients to assess the effect of weight bearing on maximal knee flexion. Three patient subgroups were investigated: patients with normal knees, patients implanted with posterior cruciate-retaining (PCR) total knee arthroplasty (TKA), and patients implanted with posterior cruciate-substituting (PS) TKA. Maximal knee flexion was determined using videofluoroscopy both in a passive, non-weight-bearing mode

Douglas A. Dennis; Richard D. Komistek; James B. Stiehl; Scott A. Walker; Kendall N. Dennis

1998-01-01

51

Effects of Intermittent Weight-Bearing and Clenbuterol on Disuse Atrophy of Rat Hindlimb Muscles  

PubMed Central

The present study was undertaken to evaluate the effects of intermittent weight-bearing (IWB) combined with ?2-agonist clenbuterol (Cb) medication for suppressing muscle atrophy during progressive disuse atrophy. Male Wistar rats (age: 8weeks, body weight: 232 ± 14 g) were divided into a control group (CON) and an experimental group. The experimental group was further subdivided into a Cb medication group under normal conditions and a hindlimb unweighting (HU) treatment group. The HU treatment group was composed of four groups: HU treatment-only, HU treatment + IWB, HU treatment + Cb medication and HU treatment + IWB + Cb medication. IWB was performed by temporarily removing the suspension device for one hour daily. On Day 14, bilateral soleus muscle (SOL) and extensor digitorum longus muscle (EDL) were extracted. Muscles from the right side were used for the measurement of contractile properties (physiological functional evaluations). Muscles from the left side were used for histochemical and biochemical analysis. During HU, IWB combined with Cb medication worked to preserve the wet weight and relative weight of SOL as compared to CON. Its contractile properties were affected by weight-bearing, while the cross-sectional area of type I fiber and protein concentration were affected by Cb. This combined therapy had marked effects on the morphology of EDL, particularly on the cross-sectional area of type II fiber. The protein concentration and contractile properties of EDL were unaffected by this combined therapy. The effect of a combination of IWB and Cb medication was specific to fiber-type and region. The data suggested that 1) IWB was effective on functional aspects such as contractile properties and useful for physical therapy, 2) Cb medication exerted the atrophy-suppressive effect in morphological parameters and manifested less effect on functional aspects. The results in this study indicated the possibility of elevating the efficacy of IWB by Cb medication in SOL.

2005-01-01

52

Innervation of three weight-bearing areas of the foot: an anatomic study and clinical implications.  

PubMed

The aim of this cadaver study is to improve our knowledge on the anatomy of the sensory fibres of the three weight-bearing areas of the plantar region. Previous studies mainly focused on the innervation of the heel but the innervation of the other two weight-bearing areas over the most medial and lateral metatarses have been neglected and are not well known. The study was carried out on 10 feet of five male cadavers. The tibial nerve was dissected down to the fat pads over the heel and the first and fifth metatarsal heads under the microscope. The distances of the branching point of the tibial nerve and origins of the medial and inferior calcaneal nerves to a line drawn from the centre of the medial malleolus to the centre of the calcaneous were all measured. The tibial nerve was divided into two branches called the lateral and medial plantar nerves 23.45 mm proximal to the predefined axis. The medial plantar nerve passed underneath the abductor hallucis muscle and gave two sensory branches to the fat pad over the first metatarsal head. The lateral plantar nerve coursed beneath the abductor hallucis and flexor digitorum brevis muscles and supplied innervation of the fat pad over the fifth metatarsal head. The sensory innervation of the heel was provided by medial calcaneal and inferior calcaneal nerves. The medial calcaneal nerve originated from the tibial nerve 41.89 mm proximal to the axis. It divided into two or three branches innervating the fat pad over the heel. The inferior calcaneal nerve originated from the lateral plantar nerve (70%) or the medial calcaneal nerve (30%) 10.66 mm proximal to the axis. This study describes the sensory fibres to the heel and the previously neglected weight-bearing areas over the first and fifth metatarses. Reconstruction of defects in these areas is very difficult so every attempt should be made to protect the sensory fibres during any surgical procedure. PMID:17400530

Unlü, Ramazan Erkin; Orbay, Hakan; Kerem, Metin; Esmer, Ali Firat; Tüccar, Eray; Sensöz, Omer

2008-01-01

53

Weight-Bearing Hip Rotation Range of Motion in Female Golfers  

PubMed Central

Background Many sports involve movements during which the lower extremity functions as a closed kinetic chain, requiring weight-bearing (WB) range of motion (ROM). Assessment of the capacity for internal and external rotation motion at the hip is typically performed with the individual in a prone, supine, or seated position. Such measurements represent ROM in a non-weight bearing (NWB) position, and, as a result, may not appropriately assess the capacity of the joint to meet the demands of the athlete's sport. To date, no research exists which documents WB hip ROM in golfers relative to the ROM demands of the golf swing or the symmetry of weight-bearing hip rotation ROM in female golfers. Objectives Weight-bearing hip rotation ROM was measured in female golfers and compared to the actual hip rotation ROM that occurred during a full golf swing. Methods Fifteen right-handed, female collegiate golfers participated in the study. The WB hip rotation ROM was measured during three different stance conditions and during full golf swings using a custom-built testing device. These actions were captured using a 3-D motion analysis system. Results The golfers WB ROM was symmetrical for external rotation and internal rotation, p = 0.648 and p = 0.078, respectively. During the backswing, the golfers used approximately 20-25% of their available WB right internal rotation, and 50-75% of their available WB left external rotation. For the downswing, the golfers used approximately 34-37% of their available WB right external rotation and 84-131% of their available WB left internal rotation. The golfers used significantly more external and internal hip rotation ROM on the left (lead) hip during both phases of the full golf swing (p < 0.001), demonstrating an asymmetrical movement pattern. Discussion In general, golfers did not exceed the measured WB ROM limits during the golf swing but did demonstrate decreased WB internal rotation on the lead hip. Conclusion Clinicians need to pay special attention to functional (WB) hip rotation ROM in female golfers in order to assess injury risk related to the rotational hip asymmetry present during the golf swing. PMID:21589662

Armstrong, Charles; Gribble, Phillip

2010-01-01

54

Weight-bearing, aerobic exercise increases markers of bone formation during short-term weight loss in overweight and obese men and women  

Microsoft Academic Search

We investigated the impact of weight-bearing, aerobic exercise– and diet-induced weight loss on markers of bone turnover during a larger study of changes in metabolic fitness during short-term weight reduction using a repeated-measures, within-subject experimental design. Subjects (N = 19) underwent 6 weeks of energy restriction (reduced by ?3140 kJ\\/d) and aerobic exercise (?1675 kJ\\/d, walking or jogging at 60%

Pamela S. Hinton; R. Scott Rector; Tom R. Thomas

2006-01-01

55

Bears, Bears, Bears!  

NSDL National Science Digital Library

What are some things you learned about bears? Use these websites to find out about bears: Parts of a Bear Polar Bears Real Story of the Three Bears The truth about bears Brown Bears Now fill in your chart! Bear Fact Sheet Listen to your teacher for further instruction on completing a book about bears! ...

Ms.Beason

2011-04-16

56

Effects of immobilization on rat hind limb muscles under non-weight-bearing conditions  

NASA Technical Reports Server (NTRS)

The effect of stretched and unstretched immobilization of a hind limb on the concentration and the metabolism of proteins in the hind-limb muscles of rats was investigated. The animals were divided into three groups: (1) weight-bearing controls, (2) tail-cast-suspended, and (3) suspended, with one hind limb immobilized with the ankle in dorsiflexion (30-40 deg angle) and the other freely moving. It was found that unloading the hind limbs for 6 days by tail cast suspension caused soleus to atrophy and reduced growth of the gastrocnemius and plantaris muscles; unloading resulted in a higher degradation rate and lower synthesis rate in both in vitro and in vivo. Chronic stretch of the unloaded soleus not only prevented its atrophy but led to significant hypertrophy, relative to weight-bearing controls, with increases in both the sarcoplasmic and myofibrillar protein fractions. Immobilizing one ankle in dorsiflexion prevented the inhibition of growth in the plantaris and gastrocnemius muscles due to unloading.

Jaspers, Stephen R.; Fagan, Julie M.; Satarug, Soisungwan; Cook, Paul H.; Tischler, Marc E.

1988-01-01

57

Alterations of collagen matrix in weight-bearing bones during skeletal unloading  

NASA Technical Reports Server (NTRS)

Skeletal unloading induces loss of bone mineral density in weight-bearing bones. The objectives of this study were to characterize the post-translational modifications of collagen of weight-bearing bones subjected to hindlimb unloading for 8 weeks. In unloaded bones, tibiae and femurs, while the overall amino acid composition was essentially identical in the unloaded and control tibiae and femurs, the collagen cross-link profile showed significant differences. Two major reducible cross-links (analyzed as dihydroxylysinonorleucine and hydroxylysinonorleucine) were increased in the unloaded bones. In addition, the ratios of the former to the latter as well as pyridinoline to deoxypyridinoline were significantly decreased in the unloaded bones indicating a difference in the extent of lysine hydroxylation at the cross-linking sites between these two groups. These results indicate that upon skeletal unloading the relative pool of newly synthesized collagen is increased and it is post-translationally altered. The alteration could be associated with impaired osteoblastic differentiation induced by skeletal unloading that results in a mineralization defect.

Shiiba, M.; Arnaud, S. B.; Tanzawa, H.; Uzawa, K.; Yamauchi, M.

2001-01-01

58

Soleus Fiber Force and Maximal Shortening Velocity After Non-Weight Bearing with Intermittent Activity  

NASA Technical Reports Server (NTRS)

This study examined the effectiveness of intermittent weight bearing (IWB) as a countermeasure to non-weight-bearing (NWB)-induced alterations in soleus type 1 fiber force (in mN), tension (P(sub o); force per fiber cross-sectional area in kN/sq m), and maximal unloaded shortening velocity (V(sub o), in fiber lengths/s). Adult rats were assigned to one of the following groups: normal weight bearing (WB), 14 days of hindlimb NWB (NWB group), and 14 days of hindlimb NWB with IWB treatments (IWB group). The IWB treatment consisted of four 10-min periods of standing WB each day. Single, chemically permeabilized soleus fiber segments were mounted between a force transducer and position motor and were studied at maximal Ca(2+) activation, after which type 1 fiber myosin heavy-chain composition was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. NWB resulted in a loss in relative soleus mass (-45%), with type 1 fibers displaying reductions in diameter (-28%) and peak isometric force (-55%) and an increase in V(sub o) (+33%). In addition, NWB induced a 16% reduction in type 1 fiber P., a 41% reduction in type 1 fiber peak elastic modulus [E(sub o), defined as ((delta)force/(delta)length x (fiber length/fiber cross-sectional area] and a significant increase in the P(sub o)/E(sub o) ratio. In contrast to NWB, IWB reduced the loss of relative soleus mass (by 22%) and attenuated alterations in type 1 fiber diameter (by 36%), peak force (by 29%), and V(sub o)(by 48%) but had no significant effect on P(sub o), E(sub o) or P(sub o)/E(sub o). These results indicate that a modest restoration of WB activity during 14 days of NWB is sufficient to attenuate type 1 fiber atrophy and to partially restore type 1 peak isometric force and V(sub o) to WB levels. However, the NWB-induced reductions in P(sub o) and E(sub o) which we hypothesize to be due to a decline in the number and stiffness of cross bridges, respectively, are considerably less responsive to this countermeasure treatment.

Widrick, Jeffrey J.; Bangart, Jill J.; Karhanek, Miloslav; Fitts, Robert H.

1996-01-01

59

Torsion of Undescended Testis in a 14-Month-Old Child Refusing to Bear Weight  

PubMed Central

In this report, we discuss a case of a 14-month-old male presenting in the emergency department with refusal to bear weight on his left leg. Plain radiographic studies revealed no evidence of effusion, fracture, or dislocation. Laboratory studies were significant for an elevated white blood cell count, erythrocyte sedimentation rate, and C-reactive protein. Further studies included unremarkable ultrasound of the left hip and normal magnetic resonance imaging (MRI) of both hips. An incidental finding on MRI was a left inguinal mass concerning an incarcerated hernia. Ultrasound of this mass demonstrated a left undescended testis within the inguinal canal and possible incarcerated paratesticular inguinal hernia. The final pathologic diagnosis of a torsed gangrenous left testicle within the inguinal canal was confirmed during surgery. PMID:22224149

Knight, Ryan M; Cuenca, Peter J

2011-01-01

60

Acetabular roof arc angles and anatomic biomechanical superior acetabular weight bearing area  

PubMed Central

Background: Acetabular fracture involves whether superior articular weight bearing area and stability of the hip are assessed by acetabular roof arc angles comprising medial, anterior and posterior. Many previous studies, based on clinical, biomechanics and anatomic superior articular surface of acetabulum showed different degrees of the angles. Anatomic biomechanical superior acetabular weight bearing area (ABSAWBA) of the femoral head can be identified as radiographic subchondral bone density at superior acetabular dome. The fracture passes through ABSAWBA creating traumatic hip arthritis. Therefore, acetabular roof arc angles of ABSAWBA were studied in order to find out that the most appropriate degrees of recommended acetabular roof arc angles in the previous studies had no ABSAWBA involvement. Materials and Methods: ABSAWBA of femoral head was identified 68 acetabular fractures and 13 isolated pelvic fractures without unstable pelvic ring injury were enrolled. Acetabular roof arc angle was measured on anteroposterior, obturator and iliac oblique view radiographs of normal contralateral acetabulum using programmatic automation controller digital system and measurement tools. Results: Average medial, anterior and posterior acetabular roof arc angles of the ABSAWBA of 94 normal acetabulum were 39.09 (7.41), 42.49 (8.15) and 55.26 (10.08) degrees, respectively. Conclusions: Less than 39°, 42° and 55° of medial, anterior and posterior acetabular roof arc angles involve ABSAWBA of the femoral head. Application of the study results showed that 45°, 45° and 62° from the previous studies are the most appropriate medial, anterior and posterior acetabular roof arc angles without involvement of the ABSAWBA respectively. PMID:25298555

Harnroongroj, Thossart; Wattanakaewsripetch, Montri; Sudjai, Narumol; Harnroongroj, Thos

2014-01-01

61

Prediction of Food Intakes, Weight Gains, Organ Weights, and Tumor Size in Tumor-bearing Rats by the Four-Parameter Mathematical Model for Physiological Responses1  

Microsoft Academic Search

Groups of male weanling rats bearing the transplantable Novikoff ascites hepatoma were fed diets containing graded levels of protein. The food intakes and weight gains were recorded daily. Seven days after inoculation of the rats with the tumor (6 days in Experiment 2), the rats were sacrificed, their organs were weighed, and the tumor and ascites fluid volumes were determined.

William T. Briscoe; L. Preston Mercer; Dixie Gimlin; Jim Ramlet

62

Benign acute childhood myositis--a rare cause of abnormal gait.  

PubMed

Benign acute childhood myositis is a rare postviral myositis seen in school-aged children after a common upper respiratory infection (URI), most commonly caused by influenza [J Microbiol Immunol Infect 2004;37:95-98]. Predominantly seen in boys, this condition causes bilateral calf tenderness and pain with ambulation, often presenting as a refusal to bear weight. To avoid activation within the gastroc-soleus complex, the child will frequently compensate with a “Frankenstein gait,” described as a stiff-legged posture with shuffling gait [CMAJ 2009;181:711-713]. The child may also walk on his toes or refuse to walk at all. This refusal to bear weight can be alarming to both providers and parents, resulting in extensive workups. We present the case of a 5-year-old boy who presented to the emergency department with a chief complaint of leg pain and refusal to walk. Further history revealed a resolved URI approximately 5 days prior. He was noted to have an elevated creatinine kinase with no evidence of renal insufficiency. He had no progression or complications, and his symptoms resolved spontaneously with minimal supportive treatment. Benign acute childhood myositis should be considered within the broad differential that surrounds a limping child or one who refuses to bear weight. Having insight into the condition with its characteristic gait abnormalities and associated URI history can often prevent extensive workups and be treated supportively in the outpatient setting. PMID:24126025

Hall, Gregory; Schranz, Craig I

2014-02-01

63

Balance Asymmetry in Parkinson’s Disease and Its Contribution to Freezing of Gait  

PubMed Central

Balance control (the ability to maintain an upright posture) is asymmetrically controlled in a proportion of patients with Parkinson’s disease. Gait asymmetries have been linked to the pathophysiology of freezing of gait. We speculate that asymmetries in balance could contribute to freezing by a) hampering the unloading of the stepping leg and/or b) leading to a preferred stance leg during gait, which then results in asymmetric gait. To investigate this, we examined the relationship between balance control and weight-bearing asymmetries and freezing. We included 20 human patients with Parkinson (tested OFF medication; nine freezers) and nine healthy controls. Balance was perturbed in the sagittal plane, using continuous multi-sine perturbations, applied by a motion platform and by a force at the sacrum. Applying closed-loop system identification techniques, relating the body sway angle to the joint torques of each leg separately, determined the relative contribution of each ankle and hip joint to the total amount of joint torque. We also calculated weight-bearing asymmetries. We determined the 99-percent confidence interval of weight-bearing and balance-control asymmetry using the responses of the healthy controls. Freezers did not have larger asymmetries in weight bearing (p?=?0.85) nor more asymmetrical balance control compared to non-freezers (p?=?0.25). The healthy linear one-to-one relationship between weight bearing and balance control was significantly different for freezers and non-freezers (p?=?0.01). Specifically, non-freezers had a significant relationship between weight bearing and balance control (p?=?0.02), whereas this relation was not significant for freezers (p?=?0.15). Balance control is asymmetrical in most patients (about 75 percent) with Parkinson’s disease, but this asymmetry is not related to freezing. The relationship between weight bearing and balance control seems to be less pronounced in freezers, compared to healthy controls and non-freezers. However, this relationship should be investigated further in larger groups of patients. PMID:25032994

Boonstra, Tjitske A.; van Vugt, Jeroen P. P.; van der Kooij, Herman; Bloem, Bastiaan R.

2014-01-01

64

IMPROVING WEIGHT BEARING ASYMMETRY IN UNILATERAL LOWER LIMB AMPUTEES BY USE OF AN INSOLE PRESSURE SENSOR-BASED  

E-print Network

PRESSURE SENSOR-BASED ELECTRO-TACTILE BIOFEEDBACK SYSTEM Pinsault N, Chenu O., Boisgontier M, Payan Y sensor-based electro-tactile biofeedback system in improving weight bearing asymmetry in lower limb in two conditions of No-biofeedback and Biofeedback. The No-biofeedback condition served as a control

Payan, Yohan

65

Comparison of dermatoscopic images of acral lentiginous melanoma and acral melanocytic nevus occurring on body weight-bearing areas  

PubMed Central

Background: Because body weight-bearing produces a shift in the horny layer, acral melanocytic nevus on the body weight-bearing area of the sole showed a regular fibrillar pattern (FP) due to slanting of the melanin columns in the horny layer. On the other hand, acral lentiginous melanoma (ALM) on the body weight-bearing area of the sole tended to show irregular fibrillar pattern showing rather structureless pigmentation instead of a parallel ridge pattern, which is due to the shift of the horny layer. Objective: To elucidate the subtle difference between the regular FP of nevus and irregular FP in ALM. Methods: In this study, the dermatoscopic features of five cases of ALM and five cases of acral melanocytic nevus on the weight-bearing area of the sole were compared. Results: All the cases with nevi showed regular FP showing regular distribution of fibrils, whereas all the melanomas showed irregular distribution of fibrils and colors. Fibrils in nevi tended to be clear at the furrows and dim at the ridges. White fibrils corresponding to the eccrine ducts in the horny layer were more often present on the ridges in ALM, which showed negative FP. Conclusion: Differentiating between the regular and irregular FP, including negative FP, might be helpful for the discrimination of melanoma from nevus. PMID:25396085

Watanabe, Soko; Sawada, Mizuki; Ishizaki, Sumiko; Kobayashi, Ken; Tanaka, Masaru

2014-01-01

66

Four calcium phosphate ceramics as bone substitutes for non-weight-bearing.  

PubMed

Calcium phosphate ceramics, beta-calcium pyrophosphate (Ca2P2O7), beta-tricalcium phosphate (Ca3(PO4)2), hydroxyapatite (Ca10(PO4)6(OH)2) and tetracalcium phosphate (Ca4(PO4)2O), were prepared. The calcium:phosphorus ratios and microporosities were 1 (31.6%), 1.5 (1.6%), 1.66 (1%) and 2 (34.6%) respectively. Samples (15 mm x 10 mm x 2 mm), abraded with No. 2000 alumina powder, were implanted into the tibial metaphysis of mature male rabbits. Failure load, when an implant detached from the bone or the bone itself broke, was measured. At 10 wk after implantation, the failure loads in beta-calcium pyrophosphate, beta-tricalcium phosphate, hydroxyapatite and tetracalcium phosphate were 31.65 +/- 9.90 N, 72.81 +/- 19.01 N, 49.49 +/- 17.25 N and 43.22 +/- 14.99 N respectively. At 25 wk after implantation, the values were 47.04 +/- 14.90 N, 71.34 +/- 19.50 N, 69.09 +/- 16.17 N and 62.03 +/- 18.62 N respectively. Histologically, bone bonding behaviour of calcium phosphate ceramics did not vary with the calcium:phosphorus ratio, as observed by contact microradiogram, Giemsa surface staining and scanning electron micrograph-electron probe micro analysis. There was no intervening soft tissue at the interface of bone and ceramics. Hydroxyapatite or tricalcium phosphate are used as bone substitutes. However, their mechanical strength is insufficient for weight-bearing and they are used as bone filler. This study showed that the apparent insignificance of strict calcium:phosphorus ratio with respect to the biological results greatly simplifies processing of calcium phosphate ceramics for clinical application. In clinical application, calcium phosphate ceramics with different Ca:P can be used as bone fillers for bone defects or bone cavities under non-weight-bearing conditions. PMID:8386554

Kitsugi, T; Yamamuro, T; Nakamura, T; Kotani, S; Kokubo, T; Takeuchi, H

1993-02-01

67

Coordination strategies for limb forces during weight-bearing locomotion in normal rats, and in rats spinalized as neonates  

PubMed Central

Some rats spinally transected as neonates (ST rats) achieve weight-supporting independent locomotion. The mechanisms of coordinated hindlimb weight support in such rats are not well understood. To examine these in such ST rats and normal rats, rats with better than 60% of weight supported steps on a treadmill as adults were trained to cross an instrumented runway. Ground reaction forces, coordination of hindlimb and forelimb forces and the motions of the center of pressure were assessed. Normal rats crossed the runway with a diagonal trot. On average hindlimbs bore about 80% of the vertical load carried by forelimbs, although this varied. Forelimbs and hindlimb acted synergistically to generate decelerative and propulsive rostrocaudal forces, which averaged 15% of body weight with maximums of 50% . Lateral forces were very small (<8% of body weight). Center of pressure progressed in jumps along a straight line with mean lateral deviations <1 cm. ST rats hindlimbs bore about 60% of the vertical load of forelimbs, significantly less compared to intact (p<0.05). ST rats showed similar mean rostrocaudal forces, but with significantly larger maximum fluctuations of up to 80% of body weight (p<0.05). Joint force-plate recordings showed forelimbs and hindlimb rostrocaudal forces in ST rats were opposing and significantly different from intact rats (p<0.05). Lateral forces were ~20% of body weight and significantly larger than in normal rats (p<0.05). Center of pressure zig-zagged, with mean lateral deviations of ~ 2cm and a significantly larger range (p<0.05). The haunches were also observed to roll more than normal rats. The locomotor strategy of injured rats using limbs in opposition was presumably less efficient but their complex gait was statically stable. Because forelimbs and hindlimbs acted in opposition, the trunk was held compressed. Force coordination was likely managed largely by the voluntary control in forelimbs and trunk. PMID:18612631

Giszter, Simon F; Davies, Michelle R; Graziani, Virginia

2010-01-01

68

Design parameters dependences on contact stress distribution in gait and jogging phases after total hip arthroplasty.  

PubMed

We have developed a mathematical model to calculate the contact stress distribution in total hip arthroplasty (THA) prosthesis between the articulating surfaces. The model uses the clearance between bearing surfaces as well as the inclination and thickness of the Ultra High Molecular Weight Poly-Ethylene (UHMWPE) cup to achieve this. We have used this mathematical model to contrast the maximal force during normal gait and during jogging. This is based on the assumption that the contact stress is proportional to the radial deformation of the cup. The results show that the magnitude of the maximal contact stress remains constant for inclination values in the range of [0-35 degrees ] and increase significantly with the cup clearance and liner thickness for inclination values in the range of [35-65 degrees ]. A major use for this model would be the calculation of spatial contact stress distribution during normal gait or jogging for different couples of bearing surfaces. PMID:18234204

Rixrath, E; Wendling-Mansuy, S; Flecher, X; Chabrand, P; Argenson, J N

2008-01-01

69

Gait phase varies over velocities.  

PubMed

We sought to characterize the percent (PT) of the phases of a gait cycle (GC) as velocity changes to establish norms for pathological gait characteristics with higher resolution technology. Ninety five healthy subjects (49 males and 46 females with age 34.9 ± 11.8 yrs, body weight 64.0 ± 11.7 kg and BMI 23.5 ± 3.6) were enrolled and walked comfortably on a 10-m walkway at self-selected slower, normal, and faster velocities. Walking was recorded with a high speed camera (250 frames per second) and the eight phases of a GC were determined by examination of individual frames for each subject. The correlation coefficients between the mean PT of the phases of the three velocities gaits and PT defined by previous publications were all greater than 0.99. The correlation coefficient between velocity and PT of gait phases is -0.83 for loading response (LR), -0.75 for mid stance (MSt), and -0.84 for pre-swing (PSw). While the PT of the phases of three velocities from this study are highly correlated with PT described by Dr. Jacquenlin Perry decades ago, actual PT of each phase varied amongst these individuals with the largest coefficient variation of 24.31% for IC with slower velocity. From slower to faster walk, the mean PT of MSt diminished from 35.30% to 25.33%. High resolution recording revealed ambiguity of some gait phase definitions, and these data may benefit GC characterization of normal and pathological gait in clinical practice. The study results indicate that one should consider individual variations and walking velocity when evaluating gaits of subjects using standard gait phase classification. PMID:24192276

Liu, Yancheng; Lu, Kun; Yan, Songhua; Sun, Ming; Lester, D Kevin; Zhang, Kuan

2014-02-01

70

Physiological responses and energy cost of walking on the Gait Trainer with and without body weight support in subacute stroke patients  

PubMed Central

Background Robotic-assisted walking after stroke provides intensive task-oriented training. But, despite the growing diffusion of robotic devices little information is available about cardiorespiratory and metabolic responses during electromechanically-assisted repetitive walking exercise. Aim of the study was to determine whether use of an end-effector gait training (GT) machine with body weight support (BWS) would affect physiological responses and energy cost of walking (ECW) in subacute post-stroke hemiplegic patients. Methods Participants: six patients (patient group: PG) with hemiplegia due to stroke (age: 66?±?15y; time since stroke: 8?±?3 weeks; four men) and 6 healthy subjects as control group (CG: age, 76?±?7y; six men). Interventions: overground walking test (OWT) and GT-assisted walking with 0%, 30% and 50% BWS (GT-BWS0%, 30% and 50%). Main Outcome Measures: heart rate (HR), pulmonary ventilation, oxygen consumption, respiratory exchange ratio (RER) and ECW. Results Intervention conditions significantly affected parameter values in steady state (HR: p?=?0.005, V’E: p?=?0.001, V'O2: p?

2014-01-01

71

A new method to assess weight-bearing distribution after central nervous system lesions in rats.  

PubMed

The aim of the present study is to assess the relevance of weight-bearing distribution (DWB) measurement in freely moving rats after stroke and thoracic spinal cord injuries. Animals were divided in 2 experiments: (1) The middle cerebral artery occlusion-reperfusion (MCAO-r) experiment containing the MCAO group in which focal brain ischaemia was induced by transient MCA occlusion and (2) the thoracic hemisection experiment containing the TH group in which a spinal cord hemisection was performed at the T10 level. A Control and respective Sham groups were also included in each experiment. Not only the pressure exerted by each paw was measured but also different ratios such as: (1) the sum of the right and the left forepaws was normalized by the sum of the right and the left hindpaws (F/H), (2) the left forepaw was normalized by the right forepaw (LF/RF), (3) the left hindpaw was normalized by the right hindpaw (LH/RH). Additionally, the times spent on 3 paws and on 4 paws were measured. Only the time spent on 4 paws was shorter in the MCAO group than in the Control (p<0.001) and in the Sham (p<0.01) groups. The LH/RH ratio of the TH group at the 1st week was lower (p<0.01) than the pre-surgical value. Moreover, its F/H ratio was superior (p<0.001) to the ones of the Control and the Sham groups. Our study indicates that DWB should be more frequently used to evaluate both the severity of central nervous system traumas and the effectiveness of pharmacological and/or rehabilitation strategies. PMID:24200548

Pertici, Vincent; Pin-Barre, Caroline; Felix, Marie-Solenne; Laurin, Jérôme; Brisswalter, Jeanick; Decherchi, Patrick

2014-02-01

72

Development and in vitro characterization of galactosylated low molecular weight chitosan nanoparticles bearing doxorubicin.  

PubMed

The aim of the present research was to evaluate the potential of galactosylated low molecular weight chitosan (Gal-LMWC) nanoparticles bearing positively charged anticancer, doxorubicin (DOX) for hepatocyte targeting. The chitosan from crab shell was depolymerized, and the lactobionic acid was coupled with LMWC using carbodiimide chemistry. The depolymerized and galactosylated polymers were characterized. Two types of Gal-LMWC(s) with variable degree of substitution were employed to prepare the nanoparticles using ionotropic gelation with pentasodium tripolyphosphate anions. Factors affecting nanoparticles formation were discussed. The nanoparticles were characterized by transmission electron microscopy and photon correlation spectroscopy and found to be spherical in the size range 106-320 nm. Relatively higher percent DOX entrapment was obtained for Gal-LMWC(s) nanoparticles than for LMWC nanoparticles. A further increase in drug entrapment was found with nanoparticles prepared by Gal-LMWC with higher degree of substitution. A hypothesis which correlates the ionic concentration of DOX in nanoparticles preparation medium and percent DOX entrapment in cationic polymer has been proposed to explain the enhanced DOX entrapment. In-vitro drug release study demonstrated an initial burst release followed by a sustained release. The targeting potential of the prepared nanoparticles was assessed by in vitro cytotoxicity study using the human hepatocellular carcinoma cell line (HepG(2)) expressing the ASGP receptors on their surfaces. The enthusiastic results showed the feasibility of Gal-LMWC(s) to entrap the cationic DOX and targeting potential of developed Gal-LMWC(s) nanoparticles to HepG(2) cell line. PMID:20414758

Jain, Nitin K; Jain, Sanjay K

2010-06-01

73

Multicomponent Training Program with Weight-Bearing Exercises Elicits Favorable Bone Density, Muscle Strength, and Balance Adaptations in Older Women  

Microsoft Academic Search

Physical exercise is advised as a preventive and therapeutic strategy against aging-induced bone weakness. In this study we\\u000a examined the effects of 8-month multicomponent training with weight-bearing exercises on different risk factors of falling,\\u000a including muscle strength, balance, agility, and bone mineral density (BMD) in older women. Participants were randomly assigned\\u000a to either an exercise-training group (ET, n = 30) or a

Elisa A. MarquesJorge; Jorge Mota; Leandro Machado; Filipa Sousa; Margarida Coelho; Pedro Moreira; Joana Carvalho

2011-01-01

74

Synergistic ablation does not affect atrophy or altered myosin heavy chain expression in the non-weight bearing soleus muscle  

NASA Technical Reports Server (NTRS)

The purpose of this study was to investigate whether the soleus muscle undergoes atrophy and alterations in myosin heavy chain (MHC) composition during non-weight bearing in the absence of synergists. Thirty-two female rats were randomly assigned to four groups: control (C), synergistic ablation (ABL) of the gastrocnemius and plantaris muscles to overload the soleus muscle, hindlimb suspension (HLS), or a combination of synergistic ablation and hindlimb suspension (HLS-ABL). After 28 days of hindlimb suspension, soleus atrophy was more pronounced in HLS (58%) than in HLS-ABL (43%) rats. Compared to C rats, non-weight bearing decreased mixed and myofibrillar protein contents and Type I MHC 49%, 45%, and 7%, respectively, in HLS animals. In addition, de novo expression of fast Type IIx and Type IIb MHC (5% and 2%, respectively) was observed in HLS animals. Similarly, when compared to C rats, mixed and myofibrillar protein contents and Type I MHC decreased 43%, 46%, and 4%, respectively, in HLS-ABL animals. Also, de novo expression of Type IIx (4%) and IIb (1%) MHC was observed. Collectively, these data indicate that the loss of muscle protein and Type I MHC, and the de novo expression of Type IIx and Type IIb MHC in the rat soleus occur independently of the presence of synergists during non-weight bearing. Furthermore, these results confirm the contention that soleus mass and MHC expression are highly sensitive to alterations in mechanical load.

Linderman, J. K.; Talmadge, R. J.; Gosselink, K. L.; Tri, P. N.; Roy, R. R.; Grindeland, R. E.

1996-01-01

75

Study of the Polycarbonate-Urethane/Metal Contact in Different Positions during Gait Cycle  

PubMed Central

Nowadays, a growing number of young and more active patients receive hip replacement. More strenuous activities in such patients involve higher friction and wear rates, with friction on the bearing surface being crucial to ensure arthroplasty survival in the long term. Over the last years, the polycarbonate-urethane has offered a feasible alternative to conventional bearings. A finite element model of a healthy hip joint was developed and adjusted to three gait phases (heel strike, mid-stance, and toe-off), serving as a benchmark for the assessment of the results of joint replacement model. Three equivalent models were made with the polycarbonate-urethane Tribofit system implanted, one for each of the three gait phases, after reproducing a virtual surgery over the respective healthy models. Standard body-weight loads were considered: 230% body-weight toe-off, 275% body-weight mid-stance, and 350% body-weight heel strike. Contact pressures were obtained for the different models. When comparing the results corresponding to the healthy model to polycarbonate-urethane joint, contact areas are similar and so contact pressures are within a narrower value range. In conclusion, polycarbonate-urethane characteristics are similar to those of the joint cartilage. So, it is a favorable alternative to traditional bearing surfaces in total hip arthroplasty, especially in young patients. PMID:25247180

Herrera, Antonio; Mateo, Jesús; Lobo-Escolar, Antonio

2014-01-01

76

Biofeedback rehabilitation of posture and weight-bearing distribution in stroke: a center of foot pressure analysis  

PubMed Central

Summary Weight bearing on the paretic lower extremity and transfer of weight from one lower extremity to the other are important goals of stroke rehabilitation. Improvements in these limb loading and weight transfer abilities have been shown to relate to improved performance of many functional activities. Unfortunately, valid and practical clinical measures of paretic lower extremity loading and weight transfer have not been identified. The purpose of this study was to quantitatively assess, through center of foot pressure (CoP) analysis of quiet upright stance control, recovery of paretic limb loading as a measure of weight transfer in early stroke subjects, testing the effectiveness of a targeted rehabilitation intervention based on audio-visual biofeedback. Thirty-seven adults with lower extremity motor impairment following unilateral, non-cerebellar stroke, were tested twice, at an interval of at least one month post stroke and following rehabilitation intervention aimed at correcting their asymmetrical weight bearing. The intervention was performed with (Study Group, SG) or without (Control Group, CG) a postural audio-visual biofeedback approach. Indices of postural stability and of balance control asymmetry were estimated by acquiring the movements of the CoP during quiet upright stance condition with or without visual input (eyes open, EO and eyes closed, EC). Clinical scales were also administered. Both the CG and the SG subjects showed improved control in upright stance posture as documented by significant improvements in the scale scores and indices of stability during both the EO and the EC condition. Only the SG showed a significantly reduced CoP index of asymmetry. The CoP index of asymmetry, correlating with clinical motor scales, is a valid measure of paretic limb loading during stroke recovery. Postural audio-visual biofeedback represented the more effective approach for reducing weight loading asymmetry of the lower limbs in stroke. PMID:25306123

De Nunzio, Alessandro Marco; Zucchella, Chiara; Spicciato, Francesca; Tortola, Paolo; Vecchione, Carmine; Pierelli, Francesco; Bartolo, Michelangelo

2014-01-01

77

A randomized controlled trial of weight-bearing versus non-weight-bearing exercise for improving physical ability after usual care for hip fracture 1 1 No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is\\/are associated  

Microsoft Academic Search

Sherrington C, Lord SR, Herbert RD. A randomized controlled trial of weight-bearing versus non-weight-bearing exercise for improving physical ability after usual care for hip fracture. Arch Phys Med Rehabil 2004;85:710–6.

Catherine Sherrington; Stephen R Lord; Robert D Herbert

2004-01-01

78

Bone loss during partial weight bearing (1/6th gravity) is mitigated by resistance and aerobic exercise in mice  

NASA Astrophysics Data System (ADS)

Astronauts on long duration missions continue to experience bone loss, as much as 1-2% each month, for up to 4.5 years after a mission. Mechanical loading of bone with exercise has been shown to increase bone formation, mass, and geometry. The aim of this study was to compare the efficacy of two exercise protocols during a period of reduced gravitational loading (1/6th body weight) in mice. Since muscle contractions via resistance exercise impart the largest physiological loads on the skeleton, we hypothesized that resistance training (via vertical tower climbing) would better protect against the deleterious musculoskeletal effects of reduced gravitational weight bearing when compared to endurance exercise (treadmill running). Young adult female BALB/cBYJ mice were randomly assigned to three groups: 1/6 g (G/6; n=6), 1/6 g with treadmill running (G/6+RUN; n=8), or 1/6 g with vertical tower climbing (G/6+CLB; n=9). Exercise was performed five times per week. Reduced weight bearing for 21 days was achieved through a novel harness suspension system. Treadmill velocity (12-20 m/min) and daily run time duration (32-51 min) increased incrementally throughout the study. Bone geometry and volumetric bone mineral density (vBMD) at proximal metaphysis and mid-diaphysis tibia were assessed by in vivo peripheral quantitative computed tomography (pQCT) on days 0 and 21 and standard dynamic histomorphometry was performed on undemineralized sections of the mid-diaphysis after tissue harvest. G/6 caused a significant decrease (P<0.001) in proximal tibia metaphysis total vBMD (-9.6%). These reductions of tibia metaphyseal vBMD in G/6 mice were mitigated in both G/6+RUN and G/6+CLB groups (P<0.05). After 21 days of G/6, we saw an absolute increase in tibia mid-diaphysis vBMD and in distal metaphysis femur vBMD in both G/6+RUN and G/6+CLB mice (P<0.05). Substantial increases in endocortical and periosteal mineralizing surface (MS/BS) at mid-diaphysis tibia in G/6+CLB demonstrate that bone formation can be increased even in the presence of reduced weight bearing. These data suggest that moderately vigorous endurance exercise and resistance training, through treadmill running or climb training mitigates decrements in vBMD during 21 days of reduced weight bearing. Consistent with our hypothesis, tower climb training, most pronounced in the tibia mid-diaphysis, provides a more potent osteogenic response compared to treadmill running.

Boudreaux, R. D.; Metzger, C. E.; Macias, B. R.; Shirazi-Fard, Y.; Hogan, H. A.; Bloomfield, S. A.

2014-06-01

79

Weight-Bearing and Mobilization in the Postoperative Care of Ankle Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Cohort Studies  

PubMed Central

Purpose To determine the effectiveness and safety of interventions used for rehabilitation after open reduction and internal fixation of ankle fractures. Methods A systematic review and meta-analysis was performed using both randomized trials and cohort studies. The effect of mobilization, weight-bearing, and unprotected weight-bearing as tolerated on postoperative recovery was compared using the Olerud Molander score, return to work/daily activities, and the rate of complications. Results A total of 25 articles were included. Ankle exercises resulted in earlier return to work and/or daily activities compared to immobilization (mean difference (MD) -20.76 days; 95% confidence interval (CI) -40.02 to -1.50). There was no difference in the rate of complications between exercises and immobilization (risk ratio (RR) 1.22; 95% CI 0.60 to 2.45) or between early and late weight-bearing (RR 1.26; 95%CI 0.56 to 2.85). Interpretation Results of this meta-analysis show that following ankle surgery, 1) active exercises accelerate return to work and daily activities compared to immobilization, 2) early weight-bearing tends to accelerate return to work and daily activities compared to late weight-bearing. Active exercises in combination with immediate weight-bearing may be a safe option. PMID:25695796

Smeeing, Diederik P. J.; Houwert, Roderick M.; Briet, Jan Paul; Kelder, Johannes C.; Segers, Michiel J. M.; Verleisdonk, Egbert Jan M. M.; Leenen, Luke P. H.; Hietbrink, Falco

2015-01-01

80

Altered response of the anterolateral abdominal muscles to simulated weight-bearing in subjects with low back pain  

PubMed Central

An important aspect of neuromuscular control at the lumbo-pelvic region is stabilization. Subjects with low back pain (LBP) have been shown to exhibit impairments in motor control of key muscles which contribute to stabilization of the lumbo-pelvic region. However, a test of automatic recruitment that relates to function has been lacking. A previous study used ultrasound imaging to show that healthy subjects automatically recruited the transversus abdominis (TrA) and internal oblique (IO) muscles in response to a simulated weight-bearing task. This task has not been investigated in subjects with LBP. The aim of this study was to compare the automatic recruitment of the abdominal muscles among subjects with and without LBP in response to the simulated weight-bearing task. Twenty subjects with and without LBP were tested. Real-time ultrasound imaging was used to assess changes in thickness of the TrA and internal oblique IO muscles as well as lateral movement (“slide”) of the anterior fascial insertion of the TrA muscle. Results showed that subjects with LBP showed significantly less shortening of the TrA muscle (P < 0.0001) and greater increases in thickness of the IO muscle (P = 0.002) with the simulated weight-bearing task. There was no significant difference between groups for changes in TrA muscle thickness (P = 0.055). This study provides evidence of changes in motor control of the abdominal muscles in subjects with LBP. This test may provide a functionally relevant and non-invasive method to investigate the automatic recruitment of the abdominal muscles in people with and without LBP. PMID:19015895

Belavý, Daniel L.; Cassar, Lana; Williams, Michelle; Wilson, Stephen J.; Richardson, Carolyn A.

2008-01-01

81

Biocompatibility and osseointegration of beta-TCP: histomorphological and biomechanical studies in a weight-bearing sheep model.  

PubMed

The aim of the study was to investigate the biocompatibility, degradation, and biomechanical properties of beta-TCP (Cerasorb) in a weight-bearing sheep model. beta-TCP implant prototypes were implanted in the tibial head of adult merino sheep. After 6 and 12 months material explants were harvested for biomechanical, histological, and histomorphometrical analysis. Corresponding bone specimens of the intact bone of the contralateral leg were used as controls in the biomechanical test. Compression tests showed higher values for maximum fracture load, yield strength, and compression modulus after 6 and 12 months compared to control. Microscopically, the implants showed good osteoconduction and were incorporated into the bone; however, relevant amounts of beta-TCP were still present after 12 months. Histomorphological results revealed that beta-TCP had partially degraded between implantation and 6 months, but its share remained constant between 6 and 12 months. The bone volume fraction in the area of the implant (46% +/- 6.5%) was initially higher than in the corresponding bone area of the contralateral leg (31% +/- 9.6%), but after 12 months declined to 29% +/- 9.4% (control: 33% +/- 8.3%), while the share of beta-TCP remained constant at 36% +/- 12.2%. These findings were supported by microradiographic data. In conclusion, in a weight bearing implantation model beta-TCP showed good biocompatibility, osseointegration and beginning degradation, even though it was not further degraded between 6 and 12 months. PMID:15264302

Koepp, Holger E; Schorlemmer, Sandra; Kessler, Stefan; Brenner, Rolf E; Claes, Lutz; Günther, Klaus-Peter; Ignatius, Anita A

2004-08-15

82

Measurement of tibial nerve excursion during ankle joint dorsiflexion in a weight-bearing position with ultrasound imaging  

PubMed Central

Background The ability of peripheral nerves to stretch and slide is thought to be of paramount importance to maintain ideal neural function. Excursion in peripheral nerves such as the tibial can be measured by analysis of ultrasound images. The aim of this study was to assess the degree of longitudinal tibial nerve excursion as the ankle moved from plantar flexion to dorsiflexion in a standardised weight-bearing position. The reliability of ultrasound imaging to measure tibial nerve excursion was also quantified. Methods The tibial nerve was imaged over two separate sessions in sixteen asymptomatic participants in a weight-bearing position. Longitudinal nerve excursion was calculated from a three-second video loop captured by ultrasound imaging using frame-by-frame cross-correlation analysis. Intraclass correlation coefficients (ICC) with 95% confidence intervals (CI) were used to assess the intra-rater reliability. Standard error of the measurement (SEM) and smallest real difference (SRD) were calculated to assess measurement error. Results Mean nerve excursion was 2.99 mm SEM ± 0.22 mm. The SRD was 0.84 mm for session 1 and 0.66 mm for session 2. Intra-rater reliability was excellent with an ICC = 0.93. Conclusions Assessment of real-time ultrasound images of the tibial nerve via frame-by-frame cross-correlation analysis is a reliable non-invasive technique to assess longitudinal nerve excursion. The relationship between foot posture and nerve excursion can be further investigated. PMID:22397397

2012-01-01

83

Effect of spaceflight on the non-weight-bearing bones of rat skeleton  

NASA Technical Reports Server (NTRS)

The effects of weightlessness on the integrated growth and remodeling of nonweight-bearing bones (the mandibles, teeth, and ribs) were studied. Rats prelabeled with tetracycline to mark the surfaces of bone and tooth formation were subjected to spaceflight conditions for 18.5 days, followed by further injections of tetracycline on days 6 and 29 postflight.Results show that spaceflight conditions did not alter the rate of periosteal bone formation in the ribs and regions of the mandibles covered by masticatory muscles, although bone formation-calcification rates were found to be impaired at those sites in the jaw that had no contiguous muscle (molar region). The remodeling activity on the alveolar bone around the buccal roots of the molar teeth was found to be significantly reduced. While total Ca, P, and hydroxyproline concentrations in the jaws, incisors, and ribs were normal after spaceflight, it was determined that weightless conditions caused a delay in the maturation of bone mineral and matrix in the jaws. These anomalies were found to be corrected by 29 days postflight. These results indicate that most of the nonweight-bearing bones of the rat skeleton are at risk to the effects of weightlessness.

Simmons, D. J.; Russell, J. E.; Winter, F.; Tran Van, P.; Vignery, A.; Baron, R.; Rosenberg, G. D.; Walker, W. V.

1983-01-01

84

Do external stimuli impact the gait of children with idiopathic toe walking? A study protocol for a within-subject randomised control trial  

PubMed Central

Introduction Frequently, toe walking gait is the result of disease processes, trauma or neurogenic influences. Idiopathic toe walking (ITW) is, by definition, the diagnosis of a toe walking gait adopted in the absence of one of these medical conditions. Long-term ITW has been associated with reduced ankle range of motion. Reported treatments have included serial casting, Botulinum toxin type A or surgery to improve the ankle range of motion. Investigating the impact of simple and non-invasive treatment options for ITW is important for future research and clinical outcomes. This study investigates the immediate impact of footwear, footwear with orthotics and whole body vibration on ITW to determine if any one intervention improves heel contact and spatial-temporal gait measures. This determination is important for future clinical trials into treatment effectiveness. Methods and analysis Design: this protocol describes a within-subject randomised controlled trial that measures changes in gait following changes in external stimuli. Participants: 15 children diagnosed with an ITW gait will be recruited from the Victorian Paediatric Rehabilitation Service at Monash Children's Hospital Toe Walking Clinic provided they have ITW and meet the inclusion criteria. Procedure: participants will have their gait recorded walking barefoot, in usual footwear, a custom-made, full-length carbon fibre orthotic in usual footwear and following whole body vibration. Outcome measures will include the presence of bilateral heel contact preintervention and postintervention, stride length (cm), stride width (cm), left and right stride time (s), left and right stance and swing percentage of the gait cycle, gait velocity (m/s), left and right foot toe in/toe out angle (°) and weight-bearing lunge pre and post each condition. Ethics and dissemination The results of this study will be published at the conclusion and have been approved by Southern Health HREC:12102B. Clinical trial registry number ACTRN12612000975897. PMID:23454667

Williams, Cylie M; Michalitsis, Joanne; Murphy, Anna; Rawicki, Barry; Haines, Terry P

2013-01-01

85

Two Patients with Osteochondral Injury of the Weight-Bearing Portion of the Lateral Femoral Condyle Associated with Lateral Dislocation of the Patella  

PubMed Central

Complications of patellar dislocation include osteochondral injury of the lateral femoral condyle and patella. Most cases of osteochondral injury occur in the anterior region, which is the non-weight-bearing portion of the lateral femoral condyle. We describe two patients with osteochondral injury of the weight-bearing surface of the lateral femoral condyle associated with lateral dislocation of the patella. The patients were 18- and 11-year-old females. Osteochondral injury occurred on the weight-bearing surface distal to the lateral femoral condyle. The presence of a free osteochondral fragment and osteochondral injury of the lateral femoral condyle was confirmed on MRI and reconstruction CT scan. Treatment consisted of osteochondral fragment fixation or microfracture, as well as patellar stabilization. Osteochondral injury was present in the weight-bearing portion of the lateral femoral condyle in both patients, suggesting that the injury was caused by friction between the patella and lateral femoral condyle when the patella was dislocated or reduced at about 90° flexion of the knee joint. These findings indicate that patellar dislocation may occur and osteochondral injury may extend to the weight-bearing portion of the femur even in deep flexion, when the patella is stabilized on the bones of the femoral groove. PMID:25506015

Inoue, Hiroaki; Atsumi, Satoru; Ichimaru, Shohei; Fujiwara, Hiroyoshi; Kubo, Toshikazu

2014-01-01

86

Gait characteristic analysis and identification based on the iPhone's accelerometer and gyrometer.  

PubMed

Gait identification is a valuable approach to identify humans at a distance. In this paper, gait characteristics are analyzed based on an iPhone's accelerometer and gyrometer,and a new approach is proposed for gait identification. Specifically, gait datasets are collected by the triaxial accelerometer and gyrometer embedded in an iPhone. Then, the datasets are processed to extract gait characteristic parameters which include gait frequency, symmetry coefficient, dynamic range and similarity coefficient of characteristic curves. Finally, a weighted voting scheme dependent upon the gait characteristic parameters is proposed forgait identification. Four experiments are implemented to validate the proposed scheme. The attitude and acceleration solutions are verified by simulation. Then the gait characteristics are analyzed by comparing two sets of actual data, and the performance of the weighted voting identification scheme is verified by 40 datasets of 10 subjects. PMID:25222034

Sun, Bing; Wang, Yang; Banda, Jacob

2014-01-01

87

Multicomponent training program with weight-bearing exercises elicits favorable bone density, muscle strength, and balance adaptations in older women.  

PubMed

Physical exercise is advised as a preventive and therapeutic strategy against aging-induced bone weakness. In this study we examined the effects of 8-month multicomponent training with weight-bearing exercises on different risk factors of falling, including muscle strength, balance, agility, and bone mineral density (BMD) in older women. Participants were randomly assigned to either an exercise-training group (ET, n = 30) or a control group (CON, n = 30). Twenty-seven subjects in the ET group and 22 in the CON group completed the study. Training was performed twice a week and was designed to load bones with intermittent and multidirectional compressive forces and to improve physical function. Outcome measures included lumbar spine and proximal femoral BMD (by dual X-ray absorptiometry), muscle strength, balance, handgrip strength, walking performance, fat mass, and anthropometric data. Potential confounding variables included dietary intake, accelerometer-based physical activity, and molecularly defined lactase nonpersistence. After 8 months, the ET group decreased percent fat mass and improved handgrip strength, postural sway, strength on knee flexion at 180°/s, and BMD at the femoral neck (+2.8%). Both groups decreased waist circumference and improved dynamic balance, chair stand performance, strength on knee extension for the right leg at 180°/s, and knee flexion for both legs at 60°/s. No associations were found between lactase nonpersistence and BMD changes. Data suggest that 8 months of moderate-impact weight-bearing and multicomponent exercises reduces the potential risk factors for falls and related fractures in older women. PMID:21113584

Marques, Elisa A; Mota, Jorge; Machado, Leandro; Sousa, Filipa; Coelho, Margarida; Moreira, Pedro; Carvalho, Joana

2011-02-01

88

Low-cost evaluation and real-time feedback of static and dynamic weight bearing asymmetry in patients undergoing in-patient physiotherapy rehabilitation for neurological conditions  

PubMed Central

Background Weight bearing asymmetry is common in patients with neurological conditions, and recent advances in gaming technology have produced force platforms that are suitable for use in a clinical setting. The aim of this research is to determine whether commercially-available Wii Balance Boards with customized software providing real-time feedback could be used in a clinical setting to evaluate and improve weight-bearing asymmetry in people with various neurological conditions. Methods Twenty participants (age?=?43.25?±?19.37 years) receiving physiotherapy as a result of a neurological condition performed three trials each of two tasks (static standing and sit-to-stand) with and without visual feedback. Vertical forces were measured using available Wii Balance Boards coupled with customized software that displayed visual feedback in real-time. Primary outcome measures included weight-bearing asymmetry as a percentage of body mass, peak force symmetry index, and a visual analogue scale score rating self-perceived level of asymmetry. Results Weight-bearing asymmetry during the static balance task was significantly reduced (Z?=??2.912, p?=?0.004, ES?=?0.65) with visual feedback. There was no significant difference (Z?=??0.336, p?=?0.737) with visual feedback for the dynamic task, however subgroup analysis indicated that those with higher weight-bearing asymmetry responded the most to feedback. Correlation analysis revealed little or no relationship between participant perception of weight-bearing asymmetry and the results for the static or dynamic balance task (Spearman’s rho: ??=?0.138, p?=?0.561 and ??=?0.018, ? =0.940 respectively). Conclusions These findings suggest that weight-bearing asymmetry can be reduced during static tasks in patients with neurological conditions using inexpensive commercially-available Wii Balance Boards coupled with customized visual feedback software. Further research is needed to determine whether real-time visual feedback is appropriate for reducing dynamic weight-bearing asymmetry, whether improvements result in improved physical function, and how cognitive and physical impairments influence the patient’s ability to respond to treatment. PMID:23849318

2013-01-01

89

Muscle contributions to support and progression during single-limb stance in crouch gait.  

PubMed

Pathological movement patterns like crouch gait are characterized by abnormal kinematics and muscle activations that alter how muscles support the body weight during walking. Individual muscles are often the target of interventions to improve crouch gait, yet the roles of individual muscles during crouch gait remain unknown. The goal of this study was to examine how muscles contribute to mass center accelerations and joint angular accelerations during single-limb stance in crouch gait, and compare these contributions to unimpaired gait. Subject-specific dynamic simulations were created for ten children who walked in a mild crouch gait and had no previous surgeries. The simulations were analyzed to determine the acceleration of the mass center and angular accelerations of the hip, knee, and ankle generated by individual muscles. The results of this analysis indicate that children walking in crouch gait have less passive skeletal support of body weight and utilize substantially higher muscle forces to walk than unimpaired individuals. Crouch gait relies on the same muscles as unimpaired gait to accelerate the mass center upward, including the soleus, vasti, gastrocnemius, gluteus medius, rectus femoris, and gluteus maximus. However, during crouch gait, these muscles are active throughout single-limb stance, in contrast to the modulation of muscle forces seen during single-limb stance in an unimpaired gait. Subjects walking in crouch gait rely more on proximal muscles, including the gluteus medius and hamstrings, to accelerate the mass center forward during single-limb stance than subjects with an unimpaired gait. PMID:20493489

Steele, Katherine M; Seth, Ajay; Hicks, Jennifer L; Schwartz, Michael S; Delp, Scott L

2010-08-10

90

The influence of a weight-bearing platform on the mechanical behavior of two Ilizarov ring fixators: tensioned wires vs. half-pins  

PubMed Central

Background A weight-bearing platform applied at the distal end of an Ilizarov external frame allows patients with hindfoot transfixations, foot deformities or plantar skin lesions to bear weight. This leads to an indirect loading of the fracture or osteotomy site. However, the effect on the fracture/osteotomy site's motion or compressive loads is unknown. The aim of this study was to analyze the mechanical effects of a weight-bearing platform on the traditional all-wire, four-ring frame in comparison to a two-ring frame consisting of half-pins. Methods Two frame configurations, with either anatomically positioned wires or half-pins, were analyzed with and without a weight-bearing platform applied underneath the distal ring. Composite tibiae with a mid-diaphyseal osteotomy of 3.5 mm were used in all the experiments. An axial load was applied with the use of a universal test machine (UTS®). Interfragmentary movements, the relative movements of bone fragments and movements between rings were recorded using displacement transducers. Compressive loads at the osteotomy site were recorded with loading cells. Results Indirect loading with a weight-bearing platform altered the force transmission through the osteotomy. Indirect loading of the tibiae decreased the extent of the axial micro-motion by 50% under the applied weight load when compared to direct weight loading (p < 0.05). The half pin frame was 25% stiffer than the wire frame under both direct and indirect loading of the tibiae (p < 0.05). Compressive loads under indirect loading were reduced by 67% in the wire frame and by 57% in the half-pin frames compared to direct loading of the bones (p < 0.05). While axial loading in the wire frames resulted in plain axial movements at the site of the osteotomy, it was coupled with translational movements and angular displacements in the half pin mountings. This effect was more apparent in the case of indirect loading. Conclusions A weight-bearing platform has substantial influence on the biomechanical performance of an Ilizarov external fixator. Half-pins induce greater stiffness to the Ilizarov external fixator and allow the usage of only one ring per bone segment, but shear stresses at the osteotomy under axial loading should be considered. The results allow an estimation of the size and direction of interfragmentary movements based on the extent of weight bearing. PMID:22152699

2011-01-01

91

Evaluation of a bisphosphonate enriched ultra-high molecular weight polyethylene for enhanced total joint replacement bearing surface functionality  

NASA Astrophysics Data System (ADS)

Each year in the United States there is an increasing trend of patients receiving total joint replacement (TJR) procedures. Approximately a half million total knee replacements (TKRs) are performed annually in the United States with increasing prevalence attributed to baby-boomers, obesity, older, and younger patients. This trend is also seen for total hip replacements (THRs) as well. The use of ultra high molecular weight polyethylene (UHMWPE) inserts in TJRs results in wear particle-induced osteolysis, which is the predominant cause for prosthesis failure and revision surgery. Sub-micron size particle generation is inevitable despite the numerous efforts in improving this bearing material. Work by others has shown that the use of oral and intravenous systemic bisphosphonates (BP) can significantly minimize periprosthetic osteolysis. However, the systemic delivery and the high solubility of BPs results in a predominant portion of the drug being excreted via the kidney without reaching its target, bone. This doctoral research project is focused on the development and evaluation of a novel method to administer BPs locally using the inherent wear of UHMWPE for possible use as an anti-osteolysis treatment. For new materials to be considered, they must be mechanically and tribologically comparable to the current gold standard, UHMWPE. In order to evaluate this material, mechanical, drug elution and tribological experiments were performed to allow assessment of material properties. Tensile tests showed comparable yield stress and pin-on-disk testing showed comparable wear to standard virgin UHMWPE. Further, drug elution tests have shown that BP was released from the enriched material both in static and dynamic conditions. Additionally, an aggressive 2 million cycle total knee simulator experiment has shown statistically similar wear results for the two materials. Overall, this research has provided the groundwork for further characterization and development of a new potential material for total joint replacements as an enhancement to standard UHMWPE. This material shows significant potential as an alternative bearing material to indirectly increase TJR longevity by addressing osteolysis related issues.

Wright-Walker, Cassandra Jane

92

Weight-bearing exercise and ground reaction forces: A 12-month randomized controlled trial of effects on bone mineral density in healthy postmenopausal women  

Microsoft Academic Search

The effects of brief' daily exercise on bone mineral density (BMD) were assessed in a randomized controlled trial in 44 healthy postmenopausal women using weight-bearing exercise in a regimen adapted from osteogenic protocols reported in animal studies. BMD was assessed masked using dual energy X-ray absorptiometry at 0, 6, and 12 months. The sites assessed were the proximal femur (neck,

E. J. Bassey; S. J. Ramsdale

1995-01-01

93

Identification of muscle synergies associated with gait transition in humans.  

PubMed

There is no theoretical or empirical evidence to suggest how the central nervous system (CNS) controls a variety of muscles associated with gait transition between walking and running. Here, we examined the motor control during a gait transition based on muscle synergies, which modularly organize functionally similar muscles. To this end, the subjects walked or ran on a treadmill and performed a gait transition spontaneously as the treadmill speed increased or decreased (a changing speed condition) or voluntarily following an experimenter's instruction at constant treadmill speed (a constant speed condition). Surface electromyograms (EMGs) were recorded from 11 lower limb muscles bilaterally. We then extracted the muscle weightings of synergies and their activation coefficients from the EMG data using non-negative matrix factorization. As a result, the gait transition was controlled by approximately 9 muscle synergies, which were common during a walking and running, and their activation profiles were changed before and after a gait transition. Near a gait transition, the peak activation phases of the synergies, which were composed of plantar flexor muscles, were shifted to an earlier phase at the walk-to-run transition, and vice versa. The shifts were gradual in the changing speed condition, but an abrupt change was observed in the constant speed condition. These results suggest that the CNS low-dimensionally regulate the activation profiles of the specific synergies based on afferent information (spontaneous gait transition) or by changing only the descending neural input to the muscle synergies (voluntary gait transition) to achieve a gait transition. PMID:25713525

Hagio, Shota; Fukuda, Mizuho; Kouzaki, Motoki

2015-01-01

94

The Pathomechanics Of Calcaneal Gait  

NASA Astrophysics Data System (ADS)

The data acquisition system employed in our laboratory includes optical, electronic and computer subsystems. Three movie camera freeze the motion for analysis. The film is displayed on a motion analyzer, and the body segment positions are recorded in a three dimensional coordinate system with Graf/pen sonic digitizer. The angular rotations are calculated by computer and automatically plotted. The force plate provides measurements of vertical force, foreaft shear, medial-lateral shear, torque, and center of pressure. Electromyograms are superimposed upon gait movies to permit measurement of muscle phasic activity. The Hycam movie camera si-multaneously films (through separate lens) the subject and oscilloscope. Movement measurements, electromyograms, and floor reaction forces provide the data base for analysis. From a study of the gait changes in five normal subjects following tibial nerve block, and from additional studies of patients with paralysis of the ankle plantar flexors, the pathomechanics of calcaneal gait can be described. Inability to transfer weight to the forward part of the foot produces ankle instability and reduction of contralateral step length. Excessive drop of the center of mass necessitates com-pensatory increased lift energy output through the sound limb to restore the height of the center of mass. Excessive stance phase ankle dorsiflexion produces knee instability requiring prolonged quadriceps muscle phasic activity.

Sutherland, David H.; Cooper, Les

1980-07-01

95

Three-Dimensional Gait Analysis Can Shed New Light on Walking in Patients with Haemophilia  

PubMed Central

In patients with haemophilia (PWH) (from Greek “blood love”), the long-term consequences of repeated haemarthrosis include cartilage damage and irreversible arthropathy, resulting in severe impairments in locomotion. Quantifying the extent of joint damage is therefore important in order to prevent disease progression and compare the efficacy of treatment strategies. Musculoskeletal impairments in PWH may stem from structural and functional abnormalities, which have traditionally been evaluated radiologically or clinically. However, these examinations are performed in a supine position (i.e., non-weight-bearing condition). We therefore suggest three-dimensional gait analysis (3DGA) as an innovative approach designed to focus on the functional component of the joint during the act of walking. This is of the utmost importance, as pain induced by weight-bearing activities influences the functional performance of the arthropathic joints significantly. This review endeavors to improve our knowledge of the biomechanical consequences of multiple arthropathies on gait pattern in adult patients with haemophilia using 3DGA. In PWH with arthropathy, the more the joint function was altered, the more the metabolic energy was consumed. 3DGA analysis could highlight the effect of an orthopedic disorder in PWH during walking. Indeed, mechanical and metabolic impairments were correlated to the progressive loss of active mobility into the joints. PMID:23766686

Lobet, Sébastien; Detrembleur, Christine; Massaad, Firas; Hermans, Cedric

2013-01-01

96

Classification and mass production technique for three-quarter shoe insoles using non-weight-bearing plantar shapes.  

PubMed

We have developed a technique for the mass production and classification of three-quarter shoe insoles via a 3D anthropometric measurement of full-size non-weight-bearing plantar shapes. The plantar shapes of fifty 40-60-year-old adults from Taiwan were categorized and, in conjunction with commercially available flat or leisure shoe models, three-quarter shoe-insole models were generated using a CAD system. Applying a rapid prototype system, these models were then used to provide the parameters for manufacturing the shoe insoles. The insoles developed in this study have been classified into S, M and L types that offer user-friendly options for foot-care providers. We concluded that these insoles can mate tightly with the foot arch and disperse the pressure in the heel and forefoot over the foot arch. Thus, practically, the pressure difference over the plantar region can be minimised, and the user can experience comfort when wearing flat or leisure shoes. PMID:18620334

Sun, Shuh-Ping; Chou, Yi-Jiun; Sue, Chun-Chia

2009-07-01

97

Phasic-to-tonic shift in trunk muscle activity relative to walking during low-impact weight bearing exercise  

NASA Astrophysics Data System (ADS)

The aim of this study was to investigate the influence of an exercise device, designed to improve the function of lumbopelvic muscles via low-impact weight-bearing exercise, on electromyographic (EMG) activity of lumbopelvic, including abdominal muscles. Surface EMG activity was collected from lumbar multifidus (LM), erector spinae (ES), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) during overground walking (OW) and exercise device (EX) conditions. During walking, most muscles showed peaks in activity which were not seen during EX. Spinal extensors (LM, ES) were more active in EX. Internal oblique and RA were less active in EX. In EX, LM and ES were active for longer than during OW. Conversely, EO and RA were active for a shorter duration in EX than OW. The exercise device showed a phasic-to-tonic shift in activation of both local and global lumbopelvic muscles and promoted increased activation of spinal extensors in relation to walking. These features could make the exercise device a useful rehabilitative tool for populations with lumbopelvic muscle atrophy and dysfunction, including those recovering from deconditioning due to long-term bed rest and microgravity in astronauts.

Caplan, Nick; Gibbon, Karl; Hibbs, Angela; Evetts, Simon; Debuse, Dorothée

2014-11-01

98

Abstract--In this paper, we explain that the human knee behavior in the weight acceptance phase of gait (first ~40% of  

E-print Network

Abstract-- In this paper, we explain that the human knee behavior in the weight acceptance phase the effects of the assistance provided by a pair of quasi- passive knee exoskeletons, which implement springs in parallel with the knee joints in the weight acceptance phase. Using the exoskeletons in a series

Dollar, Aaron M.

99

Technological Advances in Interventions to Enhance Post-Stroke Gait  

PubMed Central

Synopsis This article provides a comprehensive review of specific rehabilitation interventions used to enhance hemiparetic gait following stroke. Neurologic rehabilitation interventions may be either therapeutic resulting in enhanced motor recovery or compensatory whereby assistance or substitution for neurological deficits results in improved functional performance. Included in this review are lower extremity functional electrical stimulation (FES), body-weight supported treadmill training (BWSTT), and lower extremity robotic-assisted gait training. These post-stroke gait training therapies are predicated on activity-dependent neuroplasticity which is the concept that cortical reorganization following central nervous system injury may be induced by repetitive, skilled, and cognitively engaging active movement. All three interventions have been trialed extensively in both research and clinical settings to demonstrate a positive effect on various gait parameters and measures of walking performance. However, more evidence is necessary to determine if specific technology-enhanced gait training methods are superior to conventional gait training methods. This review provides an overview of evidence-based research which supports the efficacy of these three interventions to improve gait, as well as provide perspective on future developments to enhance post-stroke gait in neurologic rehabilitation. PMID:23598265

Sheffler, Lynne R.; Chae, John

2012-01-01

100

Gait or Walking Problems  

MedlinePLUS

... in public cause problems too, sometimes leading to social isolation. “Gait problems in ms are all over the map,” observes ... available through private or public insurance, community organizations, social service ... Problems | 8 prescription from a physician or a rehabilitation ...

101

A Robot and Control Algorithm That Can Synchronously Assist in Naturalistic Motion During Body-Weight-Supported Gait Training Following Neurologic Injury  

Microsoft Academic Search

Locomotor training using body weight support on a treadmill and manual assistance is a promising rehabilitation technique following neurological injuries, such as spinal cord injury (SCI) and stroke. Previous robots that automate this technique impose constraints on naturalistic walking due to their kinematic structure, and are typically operated in a stiff mode, limiting the ability of the patient or human

Daisuke Aoyagi; Wade E. Ichinose; Susan J. Harkema; David J. Reinkensmeyer; James E. Bobrow

2007-01-01

102

Gait Analysis Using Wearable Sensors  

PubMed Central

Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. PMID:22438763

Tao, Weijun; Liu, Tao; Zheng, Rencheng; Feng, Hutian

2012-01-01

103

New Locomotion Gaits  

Microsoft Academic Search

This paper investigates new modes of robot land locomotion, in particular statically stable non-wheeled, non-tracked locomotion. These locomotion gaits are accomplished by a reconfigurable modular robot called Polypod using a control scheme combining a small number of primitive control modes for each module. The design of Polypod is first reviewed, then two and three-dimensional locomotion gaits are described along with

Mark Yim

1994-01-01

104

A 1-year combined weight-bearing training program is beneficial for bone mineral density and neuromuscular function in older women  

Microsoft Academic Search

Forty-eight community living women 66–87 years old volunteered to participate in a 12-month prospective, randomized, controlled, trial. The aim was to determine if a combined weight-bearing training program twice a week would be beneficial to bone mineral density and neuromuscular function. The participants were pairwise age-matched and randomly assigned to either an exercise group (n=24) or a control group (n=24).

Undis Englund; Håkan Littbrand; Anna Sondell; Ulrika Pettersson; Gustaf Bucht

2005-01-01

105

Radiographic and functional results in the treatment of early stages of Charcot neuroarthropathy with a walker boot and immediate weight bearing  

PubMed Central

Background One of the most common gold standards for the treatment of Charcot neuroarthropathy (CN) in the early Eichenholtz stages I and II is immobilization with the total contact casting and lower limb offloading. However, the total amount of offloading is still debatable. Objectives This study evaluates the clinical and radiographic findings in the treatment of early stages of CN (Eichenholtz stages I and II) with a walker boot and immediate total weight-bearing status. Methods Twenty-two patients with type 2 diabetes mellitus (DM) and CN of Eichenholtz stages I and II were selected for non-operative treatment. All patients were educated about their condition, and full weight bearing was allowed as tolerated. Patients were monitored on a fortnightly basis in the earlier stages, with clinical examination, temperature measurement, and standardized weight-bearing radiographs. Their American Orthopedic Foot and Ankle Society (AOFAS) scores were determined before and after the treatment protocol. Results No cutaneous ulcerations or infections were observed in the evaluated cases. The mean measured angles at the beginning and end of the study, although showing relative increase, did not present a statistically significant difference (p > 0.05). Mean AOFAS scores showed a statistically significant improvement by the end of the study (p < 0.005). Conclusion The treatment of early stages of CN (Eichenholtz stages I and II) with emphasis on walker boot and immediate weight bearing has shown a good functional outcome, non-progressive deformity on radiographic assessment, and promising results as a safe treatment option. PMID:24179634

Parisi, Maria Candida Ribeiro; Godoy-Santos, Alexandre Leme; Ortiz, Rafael Trevisan; Sposeto, Rafael Barban; Sakaki, Marcos Hideyo; Nery, Marcia; Fernandes, Tulio Diniz

2013-01-01

106

Balancing the Rates of New Bone Formation and Polymer Degradation Enhances Healing of Weight-Bearing Allograft/Polyurethane Composites in Rabbit Femoral Defects  

PubMed Central

There is a compelling clinical need for bone grafts with initial bone-like mechanical properties that actively remodel for repair of weight-bearing bone defects, such as fractures of the tibial plateau and vertebrae. However, there is a paucity of studies investigating remodeling of weight-bearing bone grafts in preclinical models, and consequently there is limited understanding of the mechanisms by which these grafts remodel in vivo. In this study, we investigated the effects of the rates of new bone formation, matrix resorption, and polymer degradation on healing of settable weight-bearing polyurethane/allograft composites in a rabbit femoral condyle defect model. The grafts induced progressive healing in vivo, as evidenced by an increase in new bone formation, as well as a decrease in residual allograft and polymer from 6 to 12 weeks. However, the mismatch between the rates of autocatalytic polymer degradation and zero-order (independent of time) new bone formation resulted in incomplete healing in the interior of the composite. Augmentation of the grafts with recombinant human bone morphogenetic protein-2 not only increased the rate of new bone formation, but also altered the degradation mechanism of the polymer to approximate a zero-order process. The consequent matching of the rates of new bone formation and polymer degradation resulted in more extensive healing at later time points in all regions of the graft. These observations underscore the importance of balancing the rates of new bone formation and degradation to promote healing of settable weight-bearing bone grafts that maintain bone-like strength, while actively remodeling. PMID:23941405

Dumas, Jerald E.; Prieto, Edna M.; Zienkiewicz, Katarzyna J.; Guda, Teja; Wenke, Joseph C.; Bible, Jesse; Holt, Ginger E.

2014-01-01

107

The effects of ankle mobilization and active stretching on the difference of weight-bearing distribution, low back pain and flexibility in pronated-foots subjects  

PubMed Central

The purpose of this study was designed to analyze the effects mobilization and active stretching on the difference of weight-bearing distribution, low back pain, and flexibility in pronated-foot subjects. The subjects of this study were 16 chronic low back pain patients. They were randomly divided into the control and experimental group. The experimental group had used the model of ankle mobilization and calf muscle active stretching three times per week, for 4 weeks. The control group did same method without an ankle mobilization. The range of flexion and extension motion of the lumbar vertebrae and low back pain degree and difference of weight-bearing were measured before and after the experiment. The model of ankle mobilization and calf muscle stretching of pronated-foot significantly improved the range of flexion and extension motion of the vertebrae. And the visual analogue scale and distribution of weight-bearing were decreased in both of two groups. In other word, the exercise of this study showed that the model of ankle mobilization and calf muscle stretching of pronated-foot had positive effects on improving the range of flexion and extension motion of the vertebrae. The calf muscle stretching was easy and it is effective in therapy that patients by themselves and helped to recover the balance of the vertebrae to combine ankle mobilization and muscle stretching. PMID:24278874

Yoon, Ki-Seok; Park, Seong-Doo

2013-01-01

108

An in vivo study of hindfoot 3D kinetics in stage II posterior tibial tendon dysfunction (PTTD) flatfoot based on weight-bearing CT scan  

PubMed Central

Objective The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing. Methods CT scans of 15 healthy feet and 15 feet with stage II PTTD flatfoot were taken first in a non-weight-bearing condition, followed by a simulated full-body weight-bearing condition. The images of the hindfoot bones were reconstructed into 3D models. The ‘twice registration’ method in three planes was used to calculate the position of the talus relative to the calcaneus in the talocalcaneal joint, the navicular relative to the talus in talonavicular joint, and the cuboid relative to the calcaneus in the calcaneocuboid joint. Results From non- to full-body-weight-bearing condition, the difference in the talus position relative to the calcaneus in the talocalcaneal joint was 0.6° more dorsiflexed (p = 0.032), 1.4° more everted (p = 0.026), 0.9 mm more anterior (p = 0.031) and 1.0 mm more proximal (p = 0.004) in stage II PTTD flatfoot compared with that in a healthy foot. The navicular position difference relative to the talus in the talonavicular joint was 3° more everted (p = 0.012), 1.3 mm more lateral (p = 0.024), 0.8 mm more anterior (p = 0.037) and 2.1 mm more proximal (p = 0.017). The cuboid position difference relative to the calcaneus in the calcaneocuboid joint did not change significantly in rotation and translation (all p ? 0.08). Conclusion Referring to a previous study regarding both the cadaveric foot and the live foot, joint instability occurred in the hindfoot in simulated weight-bearing condition in patients with stage II PTTD flatfoot. The method used in this study might be applied to clinical analysis of the aetiology and evolution of PTTD flatfoot, and may inform biomechanical analyses of the effects of foot surgery in the future. Cite this article: Bone Joint Res 2013;2:255–63. PMID:24324193

Zhang, Y.; Xu, J.; Wang, X.; Huang, J.; Zhang, C.; Chen, L.; Wang, C.; Ma, X.

2013-01-01

109

In Vivo Motion of Femoral Condyles During Weight-Bearing Flexion After Anterior Cruciate Ligament Rupture Using Biplane Radiography  

PubMed Central

The purpose of this study was to investigate in vivo three- dimensional tibiofemoral kinematics and femoral condylar motion in knees with anterior cruciate ligament (ACL) deficiency during a knee bend activity. Ten patients with unilateral ACL rupture were enrolled. Both the injured and contralateral normal knees were imaged using biplane radiography at extension and at 15°, 30°, 60°, 90°, and 120° of flexion. Bilateral knees were next scanned by computed tomography, from which bilateral three-dimensional knee models were created. The in vivo tibiofemoral motion at each flexion position was reproduced through image registration using the knee models and biplane radiographs. A joint coordinate system containing the geometric center axis of the femur was used to measure the tibiofemoral motion. In ACL deficiency, the lateral femoral condyle was located significantly more posteriorly at extension and at 15° (p < 0.05), whereas the medial condylar position was changed only slightly. This constituted greater posterior translation and external rotation of the femur relative to the tibia at extension and at 15° (p < 0.05). Furthermore, ACL deficiency led to a significantly reduced extent of posterior movement of the lateral condyle during flexion from 15° to 60° (p < 0.05). Coupled with an insignificant change in the motion of the medial condyle, the femur moved less posteriorly with reduced extent of external rotation during flexion from 15° to 60° in ACL deficiency (p < 0.05). The medial- lateral and proximal-distal translations of the medial and lateral condyles and the femoral adduction-abduction rotation were insignificantly changed after ACL deficiency. The results demonstrated that ACL deficiency primarily changed the anterior-posterior motion of the lateral condyle, producing not only posterior subluxation at low flexion positions but also reduced extent of posterior movement during flexion from 15° to 60°. Key Points Three-dimensional tibiofemoral kinematics and femoral condylar motion in ACL-deficient knees during upright weight-bearing flexion were measured using biplane radiography with the geometric center axis. ACL deficiency caused posterior subluxation of the lateral condyle with excess external femoral rotation at early flexion positions. On flexion from 15° to 60°, the lateral condyle moved slightly posteriorly in ACL deficiency leading to reduced extent of external femoral rotation. PMID:24149168

Chen, Kaining; Yin, Li; Cheng, Liangjun; Li, Chuan; Chen, Cheng; Yang, Liu

2013-01-01

110

Magnetic Bearing  

NASA Technical Reports Server (NTRS)

AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

1996-01-01

111

Gait Generation For Legged Robots  

Microsoft Academic Search

Gait generation is the formulation and selection of a sequence of coordinated leg and body motions that propel a legged robot along a desired path. Approaches to gait generation can be classified into control, behavioral, rule-based, and constraint- based paradigms. We survey these models of gait generation and introduce the Ambler, a hexapod robot that can circulate its legs to

David Wettergreen; Chuck Thorpe

1992-01-01

112

Context based gait recognition  

NASA Astrophysics Data System (ADS)

Gait recognition has recently become a popular topic in the field of biometrics. However, the main hurdle is the insufficient recognition rate in the presence of low quality samples. The main focus of this paper is to investigate how the performance of a gait recognition system can be improved using additional information about behavioral patterns of users and the context in which samples have been taken. The obtained results show combining the context information with biometric data improves the performance of the system at a very low cost. The amount of improvement depends on the distinctiveness of the behavioral patterns and the quality of the gait samples. Using the appropriate distinctive behavioral models it is possible to achieve a 100% recognition rate.

Bazazian, Shermin; Gavrilova, Marina

2012-06-01

113

Gait adjustments in obstacle crossing, gait initiation and gait termination after a recent lower limb amputation  

Microsoft Academic Search

Objective: To describe the adjustments in gait characteristics of obstacle crossing, gait initiation and gait termination that occur in subjects with a recent lower limb amputation during the rehabilitation process.Design: Prospective and descriptive study.Subjects: Fourteen subjects with a recent transfemoral, knee disarticulation or transtibial amputation.Methods: Subjects stepped over an obstacle and initiated and terminated gait at four different times during

Aline H Vrieling; Helco G van Keeken; Tanneke Schoppen; At L Hof; Bert Otten; Jan PK Halbertsma; Klaas Postema

2009-01-01

114

The effect of frog pressure and downward vertical load on hoof wall weight-bearing and third phalanx displacement in the horse--an in vitro study.  

PubMed

A shoe was designed to combine the advantages of a reverse shoe and an adjustable heart bar shoe in the treatment of chronic laminitis. This reverse even frog pressure (REFP) shoe applies pressure uniformly over a large area of the frog solar surface. Pressure is applied vertically upward parallel to the solar surface of the frog and can be increased or decreased as required. Five clinically healthy horses were humanely euthanased and their dismembered forelimbs used in an in vitro study. Frog pressure was measured by strain gauges applied to the ground surface of the carrying tab portion of the shoe. A linear variable distance transducer (LVDT) was inserted into a hole drilled in the dorsal hoof wall. The LVDT measured movement of the third phalanx (P3) in a dorsopalmar plane relative to the dorsal hoof wall. The vertical component of hoof wall compression was measured by means of unidirectional strain gauges attached to the toe, quarter and heel of the medial hoof wall of each specimen. The entire limb was mounted vertically in a tensile testing machine and submitted to vertical downward compressive forces of 0 to 2,500 N at a rate of 5 cm/minute. The effects of increasing frog pressure on hoof wall weight-bearing and third phalanx movement within the hoof were determined. Each specimen was tested with the shoe under the following conditions: zero frog pressure; frog pressure used to treat clinical cases of chronic laminitis (7 N-cm); frog pressure clinically painful to the horse as determined prior to euthanasia; frog pressure just alleviating this pain. The specimens were also tested after shoe removal. Total weight-bearing on the hoof wall at zero frog pressure was used as the basis for comparison. Pain-causing and pain-alleviating frog pressures decreased total weight-bearing on the hoof wall (P < 0.05). Frog pressure of 7 N-cm had no statistically significant effect on hoof wall weight-bearing although there was a trend for it to decrease as load increased. Before loading, the pain-causing and pain-alleviating frog pressures resulted in a palmar movement of P3 relative to the dorsal hoof wall compared to the position of P3 at zero frog pressure (P < 0.05). This difference remained statistically significant up to 1300 N load. At higher loads, the position of P3 did not differ significantly for the different frog pressures applied. It is concluded that increased frogpressure using the REFP shoe decreases total hoof wall weight-bearing and causes palmar movement of P3 at low weight-bearing loads. Without a shoe the toe and quarter hoof wall compression remained more constant and less in magnitude, than with a shoe. PMID:12219918

Olivier, A; Wannenburg, J; Gottschalk, R D; van der Linde, M J; Groeneveld, H T

2001-12-01

115

A procedure for weighted summation of the derivatives of reflection coefficients in adaptive Schur filter with application to fault detection in rolling element bearings  

NASA Astrophysics Data System (ADS)

A procedure for feature extraction using adaptive Schur filter for damage detection in rolling element bearings is proposed in the paper. Damaged bearings produce impact signals (shocks) related with local change (loss) of stiffness in pairs: inner/outer race-rolling element. If significant disturbances do not occur (i.e. signal to noise ratio is sufficient), diagnostics is not very complicated and usually envelope analysis is used. Unfortunately, in most industrial examples, these impulsive contributions in vibration are completely masked by noise or other high energy sources. Moreover, impulses may have time varying amplitudes caused by transmission path, load and properties of noise changing in time. Thus, in order to extract time varying signal of interest, the solution would be an adaptive one. The proposed approach is based on the normalized exact least-square time-variant lattice filter (adaptive Schur filter). It is characterized by an extremely fast start-up performance, excellent convergence behavior, and fast parameter tracking capability, making this approach interesting. Schur adaptive filter consists of P sections, estimating, among others, time-varying reflection coefficients (RCs). In this paper it is proposed to use RCs and their derivatives as diagnostic features. However, it is not convenient to analyze simultaneously P signals for P sections, so instead of these, weighted sum of derivatives of RCs can be used. The key question is how to find these weight values for summation procedure. An original contributions are: application of Schur filter to bearings vibration processing, proposal of several features that can be used for detection and mentioned procedure of weighted summation of signal from sections of Schur filter. The method of signal processing is well-adapted for analysis of the non-stationary time-series, so it sounds very promising for diagnostics of machines working in time varying load/speed conditions.

Makowski, Ryszard; Zimroz, Radoslaw

2013-07-01

116

Identification of muscle synergies associated with gait transition in humans  

PubMed Central

There is no theoretical or empirical evidence to suggest how the central nervous system (CNS) controls a variety of muscles associated with gait transition between walking and running. Here, we examined the motor control during a gait transition based on muscle synergies, which modularly organize functionally similar muscles. To this end, the subjects walked or ran on a treadmill and performed a gait transition spontaneously as the treadmill speed increased or decreased (a changing speed condition) or voluntarily following an experimenter’s instruction at constant treadmill speed (a constant speed condition). Surface electromyograms (EMGs) were recorded from 11 lower limb muscles bilaterally. We then extracted the muscle weightings of synergies and their activation coefficients from the EMG data using non-negative matrix factorization. As a result, the gait transition was controlled by approximately 9 muscle synergies, which were common during a walking and running, and their activation profiles were changed before and after a gait transition. Near a gait transition, the peak activation phases of the synergies, which were composed of plantar flexor muscles, were shifted to an earlier phase at the walk-to-run transition, and vice versa. The shifts were gradual in the changing speed condition, but an abrupt change was observed in the constant speed condition. These results suggest that the CNS low-dimensionally regulate the activation profiles of the specific synergies based on afferent information (spontaneous gait transition) or by changing only the descending neural input to the muscle synergies (voluntary gait transition) to achieve a gait transition. PMID:25713525

Hagio, Shota; Fukuda, Mizuho; Kouzaki, Motoki

2015-01-01

117

Gait Stability following Concussion  

Microsoft Academic Search

PARKER, T. M., L. R. OSTERNIG, P. VAN DONKELAAR, and L. CHOU. Gait Stability following Concussion. Med. Sci. Sports Exerc., Vol. 38, No. 6, pp. 1032 - 1040, 2006. Introduction: The need to identify functional impairment following a brain injury is critical to prevent reinjury during the period of recovery. However, little is known about the effect of concussion on

TONYA M. PARKER; LOUIS R. OSTERNIG; PAUL VAN DONKELAAR; LI-SHAN CHOU

2006-01-01

118

In vivo regulation of the beta-myosin heavy chain gene in soleus muscle of suspended and weight-bearing rats  

NASA Technical Reports Server (NTRS)

In the weight-bearing hindlimb soleus muscle of the rat, approximately 90% of muscle fibers express the beta-myosin heavy chain (beta-MHC) isoform protein. Hindlimb suspension (HS) causes the MHC isoform population to shift from beta toward the fast MHC isoforms. Our aim was to establish a model to test the hypothesis that this shift in expression is transcriptionally regulated through specific cis elements of the beta-MHC promoter. With the use of a direct gene transfer approach, we determined the activity of different length beta-MHC promoter fragments, linked to a firefly luciferase reporter gene, in soleus muscle of control and HS rats. In weight-bearing rats, the relative luciferase activity of the longest beta-promoter fragment (-3500 bp) was threefold higher than the shorter promoter constructs, which suggests that an enhancer sequence is present in the upstream promoter region. After 1 wk of HS, the reporter activities of the -3500-, -914-, and -408-bp promoter constructs were significantly reduced ( approximately 40%), compared with the control muscles. However, using the -215-bp construct, no differences in promoter activity were observed between HS and control muscles, which indicates that the response to HS in the rodent appears to be regulated within the -408 and -215 bp of the promoter.

Giger, J. M.; Haddad, F.; Qin, A. X.; Baldwin, K. M.

2000-01-01

119

Toward Improved Clinical Relevance of Cartilage Insult Models in the Rabbit Knee: Surgical Access to the Habitual Weight-Bearing Region  

PubMed Central

Objective This article addresses considerations for using a posterior (popliteal) instead of anterior (para-patellar) approach for experimental insult to the rabbit knee medial femoral condyle (MFC) surface in vivo. The posterior approach is particularly advantageous when intending to address the pathomechanisms of OA associated with habitual cartilage loading, or the efficacy of a cartilage repair method, in a clinically relevant experimental setting. Design Studies using anterior versus posterior approaches for such purposes in survival rabbit models of the MFC articular surface insults were systematically surveyed. The anterior-posterior span of the primary weight-bearing region of that surface was demonstrated cadaverically. Results Of a total of 31 papers identified in 2007-2012, an anterior approach was utilized in 28 studies (> 90%). More than half (17/28) explicitly regarded the cranial half (inferior aspect) of the MFC surface as being a “weight-bearing” region. The insult site through anterior approach (identified in figures) was located in the cranial half region in all cases. Cadaverically, however, the center of habitual tibio-femoral contact locations on the MFC surface was located in the caudal half region (posterior aspect) of the MFC surface. The majority of the habitual contact region was accessible only by a posterior surgical approach. Conclusion For the above-noted purposes, use of a posterior (popliteal) approach, rather than an anterior approach, is highly recommended. PMID:24027483

Tochigi, Yuki; Buckwalter, Joseph A.; Brown, Thomas D.

2013-01-01

120

Horse Gaits Flipbooks  

NSDL National Science Digital Library

In this activity, learners explore the gait of horses by constructing flipbooks with British photographer Eadweard Muybridge's famous photographs. Learners print out three flipbooks that showcase horses walking, trotting, and galloping. Learners will explore how many hooves leave the ground at the same time when the horse trots, walks, or gallops. This activity can also be used as part of a larger unit on animation or film.

American Museum of Natural History

2012-06-26

121

Proteomic Analysis Profile of Engineered Articular Cartilage with Chondrogenic Differentiated Adipose Tissue-Derived Stem Cells Loaded Polyglycolic Acid Mesh for Weight-Bearing Area Defect Repair  

PubMed Central

The present study was designed to investigate the possibility of full-thickness defects repair in porcine articular cartilage (AC) weight-bearing area using chondrogenic differentiated autologous adipose-derived stem cells (ASCs) with a follow-up of 3 and 6 months, which is successive to our previous study on nonweight-bearing area. The isolated ASCs were seeded onto the phosphoglycerate/polylactic acid (PGA/PLA) with chondrogenic induction in vitro for 2 weeks as the experimental group prior to implantation in porcine AC defects (8?mm in diameter, deep to subchondral bone), with PGA/PLA only as control. With follow-up time being 3 and 6 months, both neo-cartilages of postimplantation integrated well with the neighboring normal cartilage and subchondral bone histologically in experimental group, whereas only fibrous tissue in control group. Immunohistochemical and toluidine blue staining confirmed similar distribution of COL II and glycosaminoglycan in the regenerated cartilage to the native one. A vivid remolding process with repair time was also witnessed in the neo-cartilage as the compressive modulus significantly increased from 70% of the normal cartilage at 3 months to nearly 90% at 6 months, which is similar to our former research. Nevertheless, differences of the regenerated cartilages still could be detected from the native one. Meanwhile, the exact mechanism involved in chondrogenic differentiation from ASCs seeded on PGA/PLA is still unknown. Therefore, proteome is resorted leading to 43 proteins differentially identified from 20 chosen two-dimensional spots, which do help us further our research on some committed factors. In conclusion, the comparison via proteome provided a thorough understanding of mechanisms implicating ASC differentiation toward chondrocytes, which is further substantiated by the present study as a perfect supplement to the former one in nonweight-bearing area. PMID:24044689

Gong, Lunli; Zhou, Xiao; Wu, Yaohao; Zhang, Yun; Wang, Chen; Zhou, Heng; Guo, Fangfang

2014-01-01

122

Growth hormone, IGF-I, and exercise effects on non-weight-bearing fast muscles of hypophysectomized rats  

NASA Technical Reports Server (NTRS)

The effects of growth hormone (GH) or insulin-like growth factor I (IGF-I) with or without exercise (ladder climbing) in countering the effects of unweighting on fast muscles of hypophysectomized rats during 10 days of hindlimb suspension were determined. Compared with untreated suspended rats, muscle weights were 16-29% larger in GH-treated and 5-15% larger in IGF-I-treated suspended rats. Exercise alone had no effect on muscle weights. Compared with ambulatory control, the medial gastrocnemius weight in suspended, exercised rats was larger after GH treatment and maintained with IGF-I treatment. The combination of GH or IGF-I plus exercise in suspended rats resulted in an increase in size of each predominant fiber type, i.e., types I, I + IIa and IIa + IIx, in the medial gastrocnemius compared with untreated suspended rats. Normal ambulation or exercise during suspension increased the proportion of fibers expressing embryonic myosin heavy chain in hypophysectomized rats. The phenotype of the medial gastrocnemius was minimally affected by GH, IGF-I, and/or exercise. These results show that there is an IGF-I, as well as a GH, and exercise interactive effect in maintaining medial gastrocnemius fiber size in suspended hypophysectomized rats.

Grossman, E. J.; Grindeland, R. E.; Roy, R. R.; Talmadge, R. J.; Evans, J.; Edgerton, V. R.

1997-01-01

123

Gait recognition and walking exercise intensity estimation.  

PubMed

Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients' exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients' attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

2014-04-01

124

Gait Recognition and Walking Exercise Intensity Estimation  

PubMed Central

Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients’ exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients’ attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

2014-01-01

125

Lateral balance control for robotic gait training.  

PubMed

For the rehabilitation of neurological patients robot-aided gait training is increasingly being used. Lack of balance training in these robotic gait trainers might contribute to the fact that they do not live up to the expectations. Therefore, in this study we developed and evaluated an algorithm to support lateral balance during walking, through controlling pelvis motions. This algorithm assists the pelvis, according to a natural pelvic sway pattern, rather than attracting it to the middle of the treadmill. The support algorithm was tested on six healthy young subjects who walked on a treadmill, while different support gains were introduced. Using a higher support gain resulted in a closer approximation of the pelvic sway towards the reference pattern. Step width and step width variability reduced when the external stabilization was provided, and the stability margin increased. This indicates that artificial stabilization reduces the need for active lateral balance control. The presented algorithm to support lateral balance provides a way to assist balance in a more physiological way, compared to attracting the subject to the centre of the treadmill. Here the user is attracted/assisted towards a more natural weight shift pattern. This also facilitates a more natural input of the load receptors, which are largely involved in the regulation of muscle activation patterns and the transitions between the different gait phases. PMID:24187182

Koopman, B; Meuleman, J H; van Asseldonk, E H F; van der Kooij, H

2013-06-01

126

Gait festination in Parkinson's disease  

Microsoft Academic Search

Background: Festinating gait (FSG) was first associated with parkinsonism by Sir James Parkinson, in his original essay on “The Shaking Palsy”. Its frequency and relation to other parkinsonian features have never been assessed.Objective: To study the relationships between gait festination and other parkinsonian clinical features among patients with Parkinson's disease (PD).Method: During an open lecture to patients with PD who

N Giladi; H Shabtai; E Rozenberg; E Shabtai

2001-01-01

127

Patient-cooperative control increases active participation of individuals with SCI during robot-aided gait training  

Microsoft Academic Search

BACKGROUND: Manual body weight supported treadmill training and robot-aided treadmill training are frequently used techniques for the gait rehabilitation of individuals after stroke and spinal cord injury. Current evidence suggests that robot-aided gait training may be improved by making robotic behavior more patient-cooperative. In this study, we have investigated the immediate effects of patient-cooperative versus non-cooperative robot-aided gait training on

Alexander Duschau-Wicke; Andrea Caprez; Robert Riener

2010-01-01

128

Pioglitazone treatment increases survival and prevents body weight loss in tumor-bearing animals: possible anti-cachectic effect.  

PubMed

Cachexia is a multifactorial syndrome characterized by profound involuntary weight loss, fat depletion, skeletal muscle wasting, and asthenia; all symptoms are not entirely attributable to inadequate nutritional intake. Adipose tissue and skeletal muscle loss during cancer cachexia development has been described systematically. The former was proposed to precede and be more rapid than the latter, which presents a means for the early detection of cachexia in cancer patients. Recently, pioglitazone (PGZ) was proposed to exhibit anti-cancer properties, including a reduction in insulin resistance and adipose tissue loss; nevertheless, few studies have evaluated its effect on survival. For greater insight into a potential anti-cachectic effect due to PGZ, 8-week-old male Wistar rats were subcutaneously inoculated with 1 mL (2×107) of Walker 256 tumor cells. The animals were randomly assigned to two experimental groups: TC (tumor + saline-control) and TP5 (tumor + PGZ/5 mg). Body weight, food ingestion and tumor growth were measured at baseline and after removal of tumor on days 7, 14 and 26. Samples from different visceral adipose tissue (AT) depots were collected on days 7 and 14 and stored at -80o C (5 to 7 animals per day/group). The PGZ treatment showed an increase in the survival average of 27.3% (P< 0.01) when compared to TC. It was also associated with enhanced body mass preservation (40.7 and 56.3%, p< 0.01) on day 14 and 26 compared with the TC group. The treatment also reduced the final tumor mass (53.4%, p<0.05) and anorexia compared with the TC group during late-stage cachexia. The retroperitoneal AT (RPAT) mass was preserved on day 7 compared with the TC group during the same experimental period. Such effect also demonstrates inverse relationship with tumor growth, on day 14. Gene expression of PPAR-?, adiponectin, LPL and C/EBP-? from cachectic rats was upregulated after PGZ. Glucose uptake from adipocyte cells (RPAT) was entirely re-established due to PGZ treatment. Taken together, the results demonstrate beneficial effects of PGZ treatment at both the early and final stages of cachexia. PMID:25807446

Beluzi, Mércia; Peres, Sidney B; Henriques, Felipe S; Sertié, Rogério A L; Franco, Felipe O; Santos, Kaltinaitis B; Knobl, Pâmela; Andreotti, Sandra; Shida, Cláudio S; Neves, Rodrigo X; Farmer, Stephen R; Seelaender, Marília; Lima, Fábio B; Batista, Miguel L

2015-01-01

129

Pioglitazone Treatment Increases Survival and Prevents Body Weight Loss in Tumor–Bearing Animals: Possible Anti-Cachectic Effect  

PubMed Central

Cachexia is a multifactorial syndrome characterized by profound involuntary weight loss, fat depletion, skeletal muscle wasting, and asthenia; all symptoms are not entirely attributable to inadequate nutritional intake. Adipose tissue and skeletal muscle loss during cancer cachexia development has been described systematically. The former was proposed to precede and be more rapid than the latter, which presents a means for the early detection of cachexia in cancer patients. Recently, pioglitazone (PGZ) was proposed to exhibit anti-cancer properties, including a reduction in insulin resistance and adipose tissue loss; nevertheless, few studies have evaluated its effect on survival. For greater insight into a potential anti-cachectic effect due to PGZ, 8-week-old male Wistar rats were subcutaneously inoculated with 1 mL (2×107) of Walker 256 tumor cells. The animals were randomly assigned to two experimental groups: TC (tumor + saline-control) and TP5 (tumor + PGZ/5 mg). Body weight, food ingestion and tumor growth were measured at baseline and after removal of tumor on days 7, 14 and 26. Samples from different visceral adipose tissue (AT) depots were collected on days 7 and 14 and stored at -80o C (5 to 7 animals per day/group). The PGZ treatment showed an increase in the survival average of 27.3% (P< 0.01) when compared to TC. It was also associated with enhanced body mass preservation (40.7 and 56.3%, p< 0.01) on day 14 and 26 compared with the TC group. The treatment also reduced the final tumor mass (53.4%, p<0.05) and anorexia compared with the TC group during late-stage cachexia. The retroperitoneal AT (RPAT) mass was preserved on day 7 compared with the TC group during the same experimental period. Such effect also demonstrates inverse relationship with tumor growth, on day 14. Gene expression of PPAR-?, adiponectin, LPL and C/EBP-? from cachectic rats was upregulated after PGZ. Glucose uptake from adipocyte cells (RPAT) was entirely re-established due to PGZ treatment. Taken together, the results demonstrate beneficial effects of PGZ treatment at both the early and final stages of cachexia. PMID:25807446

Beluzi, Mércia; Peres, Sidney B.; Henriques, Felipe S.; Sertié, Rogério A. L.; Franco, Felipe O.; Santos, Kaltinaitis B.; Knobl, Pâmela; Andreotti, Sandra; Shida, Cláudio S.; Neves, Rodrigo X.; Farmer, Stephen R.; Seelaender, Marília; Lima, Fábio B.; Batista Jr., Miguel L.

2015-01-01

130

Transgenic mice bearing a human mutant thyroid hormone beta 1 receptor manifest thyroid function anomalies, weight reduction, and hyperactivity.  

PubMed Central

BACKGROUND: Resistance to thyroid hormone (RTH) is a syndrome characterized by refractoriness of the pituitary and/or peripheral tissues to the action of thyroid hormone. Mutations in the thyroid hormone receptor beta (TR beta) gene result in TR beta 1 mutants that mediate the clinical phenotype by interfering with transcription of thyroid hormone-regulated genes via a dominant negative effect. In this study, we developed transgenic mice harboring PV, a potent dominant negative human mutant TR beta 1 devoid of thyroid hormone binding and transcriptional activation, as an animal model to understand the molecular basis of this human disease. MATERIALS AND METHODS: Standard molecular biology approaches were used to obtain a cDNA fragment containing mutant PV which was injected into the pronucleus of fertilized egg. Founders were identified by Southern analysis and the expression of PV in tissues was determined by RNA and immunohistochemistry. Thyroid function was determined by radioimmunoassays of the hormones and the behavior of mice was observed using standard methods. RESULTS: The expression of mutant PV was directed by the beta-actin promoter. Mutant PV mRNA was detected in all tissues of transgenic mice, but the levels varied with tissues and with different lines of founders. Thyroid function tests in transgenic mice with high expression of mutant PV showed a significantly (approximately 1.5-fold) higher mean serum total of L-thyroxine levels (p < 0.01) than those of nontransgenic mice. Moreover, thyroid-stimulating hormone levels were not significantly different from those of nontransgenic mice. In addition, these mice displayed decreased weights and a behavioral phenotype characterized by hyperactivity. CONCLUSIONS: These mice have phenotypic features consistent with the commonly observed clinical features of RTH and could be used as a model system to better understand the action of mutant TR beta 1 in a physiological context, which could lead to better treatment for this disease. Images FIG. 1 FIG. 2 FIG. 3 PMID:9205946

Wong, R.; Vasilyev, V. V.; Ting, Y. T.; Kutler, D. I.; Willingham, M. C.; Weintraub, B. D.; Cheng, S.

1997-01-01

131

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Side bearings. 229.69 Section 229.69 Transportation...Requirements Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight...

2011-10-01

132

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Side bearings. 229.69 Section 229.69 Transportation...Requirements Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight...

2013-10-01

133

Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. II. Experiment  

SciTech Connect

Purpose: A C-arm CT system has been shown to be capable of scanning a single cadaver leg under loaded conditions by virtue of its highly flexible acquisition trajectories. In Part I of this study, using the 4D XCAT-based numerical simulation, the authors predicted that the involuntary motion in the lower body of subjects in weight-bearing positions would seriously degrade image quality and the authors suggested three motion compensation methods by which the reconstructions could be corrected to provide diagnostic image quality. Here, the authors demonstrate that a flat-panel angiography system is appropriate for scanning both legs of subjectsin vivo under weight-bearing conditions and further evaluate the three motion-correction algorithms using in vivo data. Methods: The geometry of a C-arm CT system for a horizontal scan trajectory was calibrated using the PDS-2 phantom. The authors acquired images of two healthy volunteers while lying supine on a table, standing, and squatting at several knee flexion angles. In order to identify the involuntary motion of the lower body, nine 1-mm-diameter tantalum fiducial markers were attached around the knee. The static mean marker position in 3D, a reference for motion compensation, was estimated by back-projecting detected markers in multiple projections using calibrated projection matrices and identifying the intersection points in 3D of the back-projected rays. Motion was corrected using three different methods (described in detail previously): (1) 2D projection shifting, (2) 2D deformable projection warping, and (3) 3D rigid body warping. For quantitative image quality analysis, SSIM indices for the three methods were compared using the supine data as a ground truth. Results: A 2D Euclidean distance-based metric of subjects’ motion ranged from 0.85 mm (±0.49 mm) to 3.82 mm (±2.91 mm) (corresponding to 2.76 to 12.41 pixels) resulting in severe motion artifacts in 3D reconstructions. Shifting in 2D, 2D warping, and 3D warping improved the SSIM in the central slice by 20.22%, 16.83%, and 25.77% in the data with the largest motion among the five datasets (SCAN5); improvement in off-center slices was 18.94%, 29.14%, and 36.08%, respectively. Conclusions: The authors showed that C-arm CT control can be implemented for nonstandard horizontal trajectories which enabled us to scan and successfully reconstruct both legs of volunteers in weight-bearing positions. As predicted using theoretical models, the proposed motion correction methods improved image quality by reducing motion artifacts in reconstructions; 3D warping performed better than the 2D methods, especially in off-center slices.

Choi, Jang-Hwan [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States)] [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Maier, Andreas; Keil, Andreas; McWalter, Emily J.; Gold, Garry E.; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States)] [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Pal, Saikat [Biomedical Engineering Department, California Polytechnic State University, San Luis Obispo, California 93407 (United States)] [Biomedical Engineering Department, California Polytechnic State University, San Luis Obispo, California 93407 (United States); Beaupré, Gary S. [Musculoskeletal Research Laboratory, VA Palo Alto Health Care System, Palo Alto, California 94304 (United States)] [Musculoskeletal Research Laboratory, VA Palo Alto Health Care System, Palo Alto, California 94304 (United States)

2014-06-15

134

Effect of load carriage on gait due to firefighting air bottle configuration.  

PubMed

The air bottle configuration (mass and size) used with a firefighter's self-contained breathing apparatus may affect functional gait performance and slip/trip/fall risk, contributing to one of the most common and costly fire ground injuries to this population. To examine the potential effect of bottle mass and size on firefighter gait performance, four 30-min air bottle configurations were tested. To quantify biomechanical gait performance, kinetic and kinematic gait data were collected on 24 male firefighters while walking at normal and fast speeds during three conditions (no obstacle, 10 cm or 30 cm stationary obstacle). Bottle mass, obstacle height and walking speed - but not bottle size - were found to significantly impact gait parameters. Ten subjects (42%) contacted the taller obstacle while wearing heavier bottles, suggesting greater risk for tripping. Heavier bottles also resulted in larger forces by the trailing leg in both the anterior-posterior and vertical directions, suggesting greater risk for slipping. These results suggest that increased bottle weight may result in a decrease in gait performance and an increase in fall risk. STATEMENT OF RELEVANCE: Occupations, such as firefighting, often require use of a self-contained breathing apparatus that includes a pressurised air bottle. No systematic assessment has investigated how modest changes in load carriage due to bottle configuration (mass and size) might affect gait behaviour, especially when crossing obstacles. Bottle mass, but not size, was found to decrease gait performance and increase fall risk. PMID:20582769

Park, Kiwon; Hur, Pilwon; Rosengren, Karl S; Horn, Gavin P; Hsiao-Wecksler, Elizabeth T

2010-07-01

135

A robot for gait rehabilitation  

E-print Network

After a stroke, persons suffer from neurological impairments that affect gait, and so require rehabilitation to regain ambulatory function. While 82% of patients recover the ability to walk, current methods including ...

Roberts, Michael (Michael Henry), 1980-

2004-01-01

136

Pedicle digital pad transfer and negative pressure wound therapy for reconstruction of the weight-bearing surface after complete digital loss in a dog.  

PubMed

A young Labrador Retriever was presented for treatment of severe distal hindlimb necrosis caused by bandage ischemia. During digit amputation at the metatarsophalangeal joints, the third and fourth digital pads were salvaged and transferred to the metatarsal stump to create a weight-bearing surface. Negative pressure wound therapy (NPWT) was utilized for flap immobilization and to promote granulation tissue in the remaining wound defect. Sturdy adherence of the digital pads was achieved after only four days. The skin defect healed completely by second intention and the stump was epithelialized with a thin pad after three months. At the nine month follow-up examination, the stump had a thick hyperkeratinized pad. The dog walked and ran without any apparent signs of discomfort and compensated for the loss of limb length by extending the stifle and tarsocrural joints. Despite a challenging wound in a difficult anatomical location, digital pad flap transfer and NPWT proved successful in restoring long-term ambulation in an active large breed dog. PMID:25449188

Or, M; Van Goethem, B; Polis, I; Spillebeen, A; Vandekerckhove, P; Saunders, J; de Rooster, H

2015-03-17

137

A pilot study of a plantar sensory evaluation system for early screening of diabetic neuropathy in a weight-bearing position.  

PubMed

The purpose of this study is to develop smart equipment to quantify plantar tactile sensibility for the early diagnosis and tracking of peripheral neuropathy caused by diabetes mellitus. In this paper, we offer a new testing system that is composed of a plantar tactile stimulation platform with a small moving contactor to stretch the skin tangentially, a response switch for each tactile stimulus, a motor control box, and a personal computer (PC) for psychophysical data processing. This quantitative sensory testing system has detailed measurements available and is easy to use compared with the conventional testing devices, such as von Frey monofilaments, pin-prick testing devices, and current perception threshold testers. When using our testing system in a weight-bearing position, we observed that the plantar tactile thresholds for the tangential stretching stimulus on the plantar surface of the foot ranged from approximately 10 um to 30 um for healthy subjects. However, the threshold for a subject with diabetes was nearly three times higher than that for healthy subjects. The significant difference between these values suggests that the plantar sensory evaluation system using the lateral skin stretch stimulation can be used for early diagnosis, for the accurate staging of diabetic neuropathy, and for evaluating its progression noninvasively in a clinic and at home. PMID:25570747

Ino, Shuichi; Chikai, Manabu; Takahashi, Noriyo; Ohnishi, Tadasuke; Doi, Kohki; Nunokawa, Kiyohiko

2014-01-01

138

Bone peg fixation of a large chondral fragment in the weight-bearing portion of the lateral femoral condyle in an adolescent: a case report  

PubMed Central

Introduction Chondral fracture of the knee is relatively rare and the optimal treatment option for this injury is still controversial. In this report, we present the case of a patient with this injury who was treated surgically using the bone peg fixation procedure. There has been no literature reporting the use of this technique for fixation of a detached chondral fragment. Case presentation The patient was a 14-year-old Japanese boy who sustained a knee injury while kicking a soccer ball. Although routine radiographs showed no abnormality, magnetic resonance imaging showed a large full-thickness chondral defect in the weight-bearing portion of his lateral femoral condyle and a detached chondral fragment in the anterior region. The size of the defect (fragment) was 2cm by 1.5cm. At surgery, the chondral fragment was fixed with eight cortical bone pegs that were harvested from the anteromedial aspect of his tibia. Conclusions The postoperative magnetic resonance imaging at 4 months and the second-look arthroscopy at 12 months revealed apparent healing of the fragment. In the final follow-up examination at 26 months, a physical examination showed no swelling with recovery of full range of motion, and he could play soccer at the pre-injury level with no complaint. Based on the clinical course of this patient, it is thought that bone peg fixation can be a valuable option for fixation of a large chondral fracture of the knee. PMID:25248689

2014-01-01

139

A Patient-Invented Maneuver to Alleviate Freezing of Gait Using a Foot Loop Band  

PubMed Central

Freezing of gait (FOG) is a disabling gait disorder in parkinsonian patients characterized by the inability to initiate or continue locomotion. I herein present a 65-year-old man with Parkinson's disease who invented a unique method (foot loop band) to alleviate FOG, which has not been previously described in the literature. The mechanisms to alleviate FOG include not only facilitating mechanical weight shift, but also restoring internal cueing and driving motor commands for gait initiation. This patient-invented maneuver may be recommended for patients having intractable FOG, because it is portable, cheap and safe.

Okuma, Yasuyuki

2014-01-01

140

The influence of gait cadence on the ground reaction forces and plantar pressures during load carriage of young adults.  

PubMed

Biomechanical gait parameters-ground reaction forces (GRFs) and plantar pressures-during load carriage of young adults were compared at a low gait cadence and a high gait cadence. Differences between load carriage and normal walking during both gait cadences were also assessed. A force plate and an in-shoe plantar pressure system were used to assess 60 adults while they were walking either normally (unloaded condition) or wearing a backpack (loaded condition) at low (70 steps per minute) and high gait cadences (120 steps per minute). GRF and plantar pressure peaks were scaled to body weight (or body weight plus backpack weight). With medium to high effect sizes we found greater anterior-posterior and vertical GRFs and greater plantar pressure peaks in the rearfoot, forefoot and hallux when the participants walked carrying a backpack at high gait cadences compared to walking at low gait cadences. Differences between loaded and unloaded conditions in both gait cadences were also observed. PMID:25766421

Castro, Marcelo P; Figueiredo, Maria Cristina; Abreu, Sofia; Sousa, Helena; Machado, Leandro; Santos, Rubim; Vilas-Boas, João Paulo

2015-07-01

141

How crouch gait can dynamically induce stiff-knee gait.  

PubMed

Children with cerebral palsy frequently experience foot dragging and tripping during walking due to a lack of adequate knee flexion in swing (stiff-knee gait). Stiff-knee gait is often accompanied by an overly flexed knee during stance (crouch gait). Studies on stiff-knee gait have mostly focused on excessive knee muscle activity during (pre)swing, but the passive dynamics of the limbs may also have an important effect. To examine the effects of a crouched posture on swing knee flexion, we developed a forward-dynamic model of human walking with a passive swing knee, capable of stable cyclic walking for a range of stance knee crouch angles. As crouch angle during stance was increased, the knee naturally flexed much less during swing, resulting in a 'stiff-knee' gait pattern and reduced foot clearance. Reduced swing knee flexion was primarily due to altered gravitational moments around the joints during initial swing. We also considered the effects of increased push-off strength and swing hip flexion torque, which both increased swing knee flexion, but the effect of crouch angle was dominant. These findings demonstrate that decreased knee flexion during swing can occur purely as the dynamical result of crouch, rather than from altered muscle function or pathoneurological control alone. PMID:20162360

van der Krogt, Marjolein M; Bregman, Daan J J; Wisse, Martijn; Doorenbosch, Caroline A M; Harlaar, Jaap; Collins, Steven H

2010-04-01

142

Hearing Loss and Gait Speed Among Older Adults in the United States  

PubMed Central

Background Previous studies have suggested that hearing loss, which is highly prevalent but undertreated in older adults, may be associated with gait and physical functioning. Determining if hearing loss is independently associated with gait speed is critical toward understanding whether hearing rehabilitative interventions could help mitigate declines in physical functioning in older adults. Methods We analyzed cross-sectional data from the 1999–2002 cycles of the National Health and Nutritional Examination Survey during which participants 50–69 years (n = 1180) underwent hearing and gait speed assessments. Hearing was defined by a pure tone average of hearing thresholds at 0.5–4 kHz tones in the better-hearing ear. Gait speed was obtained in a timed 20-foot (6.1 meter) walk. Linear and logistic regression models were used to examine the association between hearing loss and gait speed while adjusting for demographic and cardiovascular risk factors. Analyses incorporated sampling weights to yield results generalizable to the U.S. population. Results In a model adjusted for demographic and cardiovascular risk factors, a 25 dB hearing loss was associated with slower gait speed (?0.05 m/s per 25 dB HL [95% CI: ?0.09 – ?0.02]) and a nearly two-fold increased odds of having a gait speed < 1.0 m/s (OR 2.0, 95% CI: 1.2 –3.3). The reduction in gait speed associated with a 25 dB hearing loss was equivalent to that associated with an age difference of nearly 12 years. Conclusions Greater hearing loss is independently associated with slower gait speed. Further studies investigating the mechanistic basis of this association and whether hearing rehabilitative interventions could affect gait and physical functioning are needed. PMID:23177614

Li, Lingsheng; Simonsick, Eleanor M.; Ferrucci, Luigi; Lin, Frank R.

2012-01-01

143

Polar Bears  

NSDL National Science Digital Library

Use the following websites to answer questions about the rapid disappearance of polar bears in the Arctic region. Polar Bear picture Polar Bear Tracker 1: What region in the world has the fewest polar bears? 2: Using the internet as a resource, provide some reasons as to why this region is suffering from the most polar bear differences? Polar Bears Change Diet 1: Why are polar bears having to change their diets? 2: List some other factors (besides diet) in the ...

Mr. Thomas

2010-09-27

144

A practical magnetic bearing  

NASA Technical Reports Server (NTRS)

A small compact magnetic bearing design developed and tested features a bearing capable of supporting over ten times its own weight, dimensioned 8 cm diam by 3.75 cm, with rare-earth cobalt magnets. Only 1% of the device payload figures as part of the magnetic suspension. The design is servoed in two axes and exhibits inherent stability in three more degrees of freedom, with full rotational freedom in the desired axis. Capacitive radial gap sensing allows stiff servoing of the rotation axis. Differential sensing and EM control linearize control functions. Low power drain, simple fabrication and assembly, and larger clearances than in air bearings or ball bearings are reported

Studer, P. A.

1977-01-01

145

Biometric Gait Recognition Jeffrey E. Boyd1  

E-print Network

biometrics [1]. There are also several confounding properties of gait as a biometric. Unlike finger prints recognition systems, and uses of gait anal- ysis beyond biometric identification. M. Tistarelli, J. Bigun

Boyd, Jeffrey E.

146

The effects of head movement and walking speed on gait parameters in patients with chronic neck pain.  

PubMed

It has been documented that neck pain can influence sensorimotor function. However, little is known about the effects of head movement and walking speed on gait characteristics in patients with neck pain. The aim of this study was to determine gait characteristics of patients with neck pain during walking with different head movements and gait speeds as compared to a control group without neck pain. Twenty women aged between 18 and 59 years with chronic neck pain (>3 months) and 20 healthy controls of similar age, weight and height were recruited into the study. Participants with neck pain completed the Neck Disability Index and Visual Analogue Pain Scale. The experiment consisted of two walking sessions. The first session included walking with head straight, head up-down, and head turns from side to side. The second session included walking at comfortable and maximum speeds. Each trial was performed twice. Gait parameters measured using GAITRite walkway system were step length, stride length, step time, stride time, step width, cadence and gait speed. Patients with chronic neck pain demonstrated a narrower step width, a shorter step length and a slower gait speed during walking with the head movements and at maximum speed compared to the control group (all p < 0.05). Maximum gait speed was moderately correlated with pain intensity and disability (p < 0.01). The results suggest that patients with chronic neck pain have gait disturbances. This supports the notion that assessment of gait should be addressed in patients with persistent neck pain. PMID:24144513

Uthaikhup, Sureeporn; Sunkarat, Somporn; Khamsaen, Khanamporn; Meeyan, Kitti; Treleaven, Julia

2014-04-01

147

Weight-Bearing MR Imaging as an Option in the Study of Gravitational Effects on the Vocal Tract of Untrained Subjects in Singing Phonation  

PubMed Central

Magnetic Resonance Imaging (MRI) of subjects in a supine position can be used to evaluate the configuration of the vocal tract during phonation. However, studies of speech phonation have shown that gravity can affect vocal tract shape and bias measurements. This is one of the reasons that MRI studies of singing phonation have used professionally trained singers as subjects, because they are generally considered to be less affected by the supine body position and environmental distractions. A study of untrained singers might not only contribute to the understanding of intuitive singing function and aid the evaluation of potential hazards for vocal health, but also provide insights into the effect of the supine position on singers in general. In the present study, an open configuration 0.25 T MRI system with a rotatable examination bed was used to study the effect of body position in 20 vocally untrained subjects. The subjects were asked to sing sustained tones in both supine and upright body positions on different pitches and in different register conditions. Morphometric measurements were taken from the acquired images of a sagittal slice depicting the vocal tract. The analysis concerning the vocal tract configuration in the two body positions revealed differences in 5 out of 10 measured articulatory parameters. In the upright position the jaw was less protruded, the uvula was elongated, the larynx more tilted and the tongue was positioned more to the front of the mouth than in the supine position. The findings presented are in agreement with several studies on gravitational effects in speech phonation, but contrast with the results of a previous study on professional singers of our group where only minor differences between upright and supine body posture were observed. The present study demonstrates that imaging of the vocal tract using weight-bearing MR imaging is a feasible tool for the study of sustained phonation in singing for vocally untrained subjects. PMID:25379885

Traser, Louisa; Burdumy, Michael; Richter, Bernhard; Vicari, Marco; Echternach, Matthias

2014-01-01

148

Distally based sural fasciomyocutaneous flap: anatomic study and modified technique for complicated wounds of the lower third leg and weight bearing heel.  

PubMed

The reconstruction of the distal third leg and weight-bearing heel, especially when complicated with infection and/or dead space, remains a challenge in reconstructive surgery. The distally based sural neurofasciomyocutaneous flap has been proved a valuable tool in repair of the soft tissue defects of those areas. In this report, we present the results of the anatomical study on vascular communication between the suprafascial sural neurovascular axis and the deep gastrocnemius muscle and a modified technique in clinical applications for reconstruction of the soft tissue defects in the distal lower leg and heel. Six lower limbs of fresh cadavers were injected with red gelatin and dissected. A constant vascular connection with average four musculo-fasciocutaneous perforators with diameter 0.2-0.5 mm was identified in the overlapping area between the suprafascial sural neurovascular axis and the deep gastrocnemius muscle. Based on these findings, a modified distally based sural neurofasciomyocutaneous flap including the distal gastrocnemius muscle component was designed and used for repairs of the soft tissue defects in the distal lower limb and plantar heel pad in six patients. The blood supplies of flaps comprised either the peroneal perforator and adipofascial pedicle or the peroneal perforator only. The average size of the fasciocutaneous flap was 51 cm(2), and the muscle component 17.7 cm(2). All flaps survived uneventfully. Our results suggest that this technical modification could provide wider range for applications of the distally based sural neurofasciomyocutaneous flap in repair of the soft tissue defects of the lower extremity and heel. PMID:19031395

Chang, Shi-Min; Zhang, Kai; Li, Hai-Feng; Huang, Yi-Gang; Zhou, Jia-Qian; Yuan, Feng; Yu, Guang-Rong

2009-01-01

149

High frequency circular translation pin-on-disk method for accelerated wear testing of ultrahigh molecular weight polyethylene as a bearing material in total hip arthroplasty.  

PubMed

The temporal change of the direction of sliding relative to the ultrahigh molecular weight polyethylene (UHMWPE) component of prosthetic joints is known to be of crucial importance with respect to wear. One complete revolution of the resultant friction vector is commonly called a wear cycle. It was hypothesized that in order to accelerate the wear test, the cycle frequency may be substantially increased if the circumference of the slide track is reduced in proportion, and still the wear mechanisms remain realistic and no overheating takes place. This requires an additional slow motion mechanism with which the lubrication of the contact is maintained and wear particles are conveyed away from the contact. A three-station, dual motion high frequency circular translation pin-on-disk (HF-CTPOD) device with a relative cycle frequency of 25.3 Hz and an average sliding velocity of 27.4 mm/s was designed. The pins circularly translated at high frequency (1.0 mm per cycle, 24.8 Hz, clockwise), and the disks at low frequency (31.4mm per cycle, 0.5 Hz, counter-clockwise). In a 22 million cycle (10 day) test, the wear rate of conventional gamma-sterilized UHMWPE pins against polished CoCr disks in diluted serum was 1.8 mg per 24 h, which was six times higher than that in the established 1 Hz CTPOD device. The wear mechanisms were similar. Burnishing of the pin was the predominant feature. No overheating took place. With the dual motion HF-CTPOD method, the wear testing of UHMWPE as a bearing material in total hip arthroplasty can be substantially accelerated without concerns of the validity of the wear simulation. PMID:25498368

Saikko, Vesa

2015-01-21

150

Bearing system  

DOEpatents

A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

Kapich, Davorin D. (Carlsbad, CA)

1987-01-01

151

A New Free Gait Generation for Quadrupeds Based on Primary\\/Secondary Gait  

Microsoft Academic Search

A method of free gait generation for quadrupeds is presented by introducing the primary\\/secondary gait. The primary gait is a fixed sequence of leg transfers with modified leg-ends kinematic limits according to the obstacle presence, while the secondary gait is a flexible gait which is generated to adjust the leg-end position. Using the proposed method, a machine tends to move

Shaoping Bai; Kin Huat Low; Gerald Seet; Teresa Zielinska

1999-01-01

152

A mechanical energy analysis of gait initiation  

NASA Technical Reports Server (NTRS)

The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

Miller, C. A.; Verstraete, M. C.

1999-01-01

153

Energy Expenditure During Cane-Assisted Gait in Patients with Knee Osteoarthritis  

PubMed Central

OBJECTIVE To compare the energy expenditure in patients with unilateral knee osteoarthritis while walking with canes of different lengths. METHODS A quasi-experimental study (single-group) was carried out on thirty patients with unilateral knee osteoarthritis. An adjustable aluminum cane was used, and three different cane lengths were determined for each subject: C1 – length from the floor to the greater trochanter; C2 – length from the floor to the distal wrist crease; and C3 – length obtained by the formula: height x 0.45 + 0.87 m. Resting and walking heart rates were measured with a Polar hear rate meter. Walking speed was calculated by the time required for the patient to walk 10 m. Gait energy cost was estimated using the physiological cost index, and results were compared. RESULTS The sample consisted of 25 women and five men (average age of 68 years). Statistically significant differences in physiological cost index measurements were observed between unassisted walking and assisted walking with a cane of any length (p<0.001), as well as between walking with a C2-length cane and unassisted walking, and walking with a C1-length cane and walking with a C3-length cane (p=0.001; p = 0.037; p=0.001; respectively). CONCLUSION These data demonstrate that small alterations in the length of canes used for weight-bearing ambulation in patients with unilateral knee osteoarthritis increase the energy expenditure measured by the physiological cost index during walking. Further studies are needed for a more precise quantification of the increase in energy expenditure during cane-assisted gait and an assessment of the effectiveness of cane use in relieving pain and improving function in patients with knee osteoarthritis. PMID:18438573

Jones, Anamaria; Alves, Ana Claudia Monteiro; de Oliveira, Leda Magalhães; Saad, Marcelo; Natour, Jamil

2008-01-01

154

Gait and jump analysis in healthy cats using a pressure mat system.  

PubMed

Physical orthopaedic examination in cats does not always reveal signs of lameness and no objective gait analysis method has yet been standardised for use in cats. The aims of the present study were to define appropriate parameters for pressure mat analyses during walk and jump, and to define reference values for gait parameters of healthy cats. Further, the distribution of the vertical force within the paws and the influence of a non-centred head position were investigated. The hypothesis was that cats have a symmetrical gait, a front/hindlimb asymmetry similar to dogs, and that peak vertical force (PVF) and vertical impulse (VI) have high intraclass correlation coefficients, confirming the reliability of these parameters. Data for walking (n = 46) showed gait symmetry indices of close to 1.0, besides PVF front/hind (1.3 ± 0.2). The PVF front/hind for jumping cats (n = 16) was 1.7 ± 0.6. Results from the distribution of the vertical force within the paw (n = 39) showed that the main weight during a strike is transferred from the caudal towards the craniomedial part of the paw. The findings support the hypothesis that healthy cats have similar gait symmetry to healthy dogs and that PVF and VI are reliable gait parameters. In conclusion, the present study provides a reference range for healthy cats. Further studies are needed to investigate gait parameters in cats with orthopaedic disease. PMID:25239912

Stadig, Sarah M; Bergh, Anna K

2014-09-19

155

Biomechanics of Gait during Pregnancy  

PubMed Central

Introduction. During pregnancy women experience several changes in the body's physiology, morphology, and hormonal system. These changes may affect the balance and body stability and can cause discomfort and pain. The adaptations of the musculoskeletal system due to morphological changes during pregnancy are not fully understood. Few studies clarify the biomechanical changes of gait that occur during pregnancy and in postpartum period. Purposes. The purpose of this review was to analyze the available evidence on the biomechanical adaptations of gait that occur throughout pregnancy and in postpartum period, specifically with regard to the temporal, spatial, kinematic, and kinetic parameters of gait. Methods. Three databases were searched and 9 studies with a follow-up design were retrieved for analysis. Results. Most studies performed temporal, spatial, and kinematic analysis. Only three studies performed kinetic analysis. Conclusion. The adaptation strategies to the anatomical and physiological changes throughout pregnancy are still unclear, particularly in a longitudinal perspective and regarding kinetic parameters. PMID:25587566

Vieira, Filomena

2014-01-01

156

Increasing weight-bearing physical activity and calcium-rich foods to promote bone mass gains among 9–11 year old girls: outcomes of the Cal-Girls study  

Microsoft Academic Search

BACKGROUND: A two-year, community-based, group-randomized trial to promote bone mass gains among 9–11 year-old girls through increased intake of calcium-rich foods and weight-bearing physical activity was evaluated. METHODS: Following baseline data collection, 30 5th-grade Girl Scout troops were randomized to a two-year behavioral intervention program or to a no-treatment control group. Evaluations were conducted at baseline, one year, and two

Simone A French; Mary Story; Jayne A Fulkerson; John H Himes; Peter Hannan; Dianne Neumark-Sztainer; Kristine Ensrud

2005-01-01

157

Normative spatiotemporal gait parameters in older adults.  

PubMed

While factor analyses have characterized pace, rhythm and variability as factors that explain variance in gait performance in older adults, comprehensive analyses incorporating many gait parameters have not been undertaken and normative data for many of those parameters are lacking. The purposes of this study were to conduct a factor analysis on nearly two dozen spatiotemporal gait parameters and to contribute to the normative database of gait parameters from healthy, able-bodied men and women over the age of 70. Data were extracted from 294 participants enrolled in the Mayo Clinic Study of Aging. Spatiotemporal gait data were obtained as participants completed two walks across a 5.6-m electronic walkway (GAITRite(®)). Five primary domains of spatiotemporal gait performance were identified: a "rhythm" domain was characterized by cadence and temporal parameters such as stride time; a "phase" domain was characterized by temporophasic parameters that constitute distinct divisions of the gait cycle; a "variability" domain encompassed gait cycle and step variability parameters; a "pace" domain was characterized by parameters that included gait speed, step length and stride length; and a "base of support" domain was characterized by step width and step width variability. Several domains differed between men and women and differed across age groups. Reference values of 23 gait parameters are presented which researchers or clinicians can use for assessing and interpreting gait dysfunction in aging persons. PMID:21531139

Hollman, John H; McDade, Eric M; Petersen, Ronald C

2011-05-01

158

Polar Bear Polar Bear  

NSDL National Science Digital Library

In this lesson, students will listen for key details in a nonfiction text about polar bears. They will work at completing a graphic organizer with the teacher to help organize their thinking and understanding of key details about a text. They will also complete an independent assignment where they will draw or write two things that they learned about the topic.

Kelly Burgess

2012-09-11

159

Specific influences of cerebellar dysfunctions on gait.  

PubMed

Cerebellar ataxic gait is characterized by unsteady movements and variable gait patterns. Previous studies have successfully identified pathological changes of balance-related gait parameters. However, it has been difficult to demonstrate deficits of joint coordination and the control of limb dynamics. This has motivated the hypothesis that cerebellar ataxic gait might be affected predominantly by balance impairments. We investigated the influences of different types of cerebellar dysfunction on the gait patterns of patients suffering from degenerative cerebellar disease (13 patients, five females, 50.4 +/- 14.4 years). Walking patterns were quantitatively analysed combining standard gait measures and novel measures for the characterization of the spatial and the temporal variability of intra-joint coordination patterns. The temporal variability of gait patterns was significantly correlated with a subscale of the clinical ataxia scale (ICARS) that rates deficits of the control of limb dynamics and intra-limb coordination for goal-directed movements. This suggests that common cerebellar mechanisms might be involved in coordination during voluntary limb control and ataxic gait. The tested standard gait parameters correlated predominantly with clinical measures for balance-related abnormalities. These results imply that ataxic gait is influenced by both balance-related impairments and deficits related to limb control and intra-limb coordination. Applying the same analysis to gait patterns from patients with peripheral vestibular failure (six patients, four females, 47.8 +/- 14.3 years) and Parkinson's disease (eight patients, two females, 60.7 +/- 10.6 years), we found comparable abnormalities in balance-related gait parameters and general gait variability, but significantly lower increases of temporal variability. This implies that increased temporal variability of intra-limb coordination is a specific characteristic of cerebellar dysfunction, which does not arise for other movement disorders that also cause balance deficits and increased gait variability. PMID:17287287

Ilg, Winfried; Golla, Heidrun; Thier, Peter; Giese, Martin A

2007-03-01

160

The syndrome of senile gait  

Microsoft Academic Search

Infrared computed stroboscopic photometry was used to quantify the kinematic profiles of walking in 10 elderly patients with symmetrical neurological disturbances of gait and in 19 age-matched neurologically healthy people. Clinical examination of the patients revealed similar profiles of walking even though their diagnoses were vascular dementia (2), normal pressure hydrocephalus (2), Alzheimer dementia with possible normal pressure hydrocephalus (2),

Rodger J. Elble; Larry Hughes; Constance Higgins

1992-01-01

161

Bear Scratch  

USGS Multimedia Gallery

When looking for a place to set up a trapping location, scientists look for existing bear sign such as scratches on trees and bear scat. Sometimes traps are set in areas that have no obvious bear sign to determine if indeed bears are present....

162

Genetic feature selection for gait recognition  

NASA Astrophysics Data System (ADS)

Many research studies have demonstrated that gait can serve as a useful biometric modality for human identification at a distance. Traditional gait recognition systems, however, have mostly been evaluated without explicitly considering the most relevant gait features, which might have compromised performance. We investigate the problem of selecting a subset of the most relevant gait features for improving gait recognition performance. This is achieved by discarding redundant and irrelevant gait features while preserving the most informative ones. Motivated by our previous work on feature subset selection using genetic algorithms (GAs), we propose using GAs to select an optimal subset of gait features. First, features are extracted using kernel principal component analysis (KPCA) on spatiotemporal projections of gait silhouettes. Then, GA is applied to select a subset of eigenvectors in KPCA space that best represents a subject's identity. Each gait pattern is then represented by projecting it only on the eigenvectors selected by the GA. To evaluate the effectiveness of the selected features, we have experimented with two different classifiers: k nearest-neighbor and Naïve Bayes classifier. We report considerable gait recognition performance improvements on the Georgia Tech and CASIA databases.

Tafazzoli, Faezeh; Bebis, George; Louis, Sushil; Hussain, Muhammad

2015-01-01

163

Fixed-Bearing Total Ankle Replacement (TAR) Improves Gait Function  

MedlinePLUS

... can be reached at tstanton@aaos.org Bottom Line Current literature on the new generation of fixed- ... January 2014 - PRIVACY POLICY - Disclaimers & Agreement Advertising & Sponsorship Contact AAOS Technical Requirements Careers 9400 West Higgins Road ...

164

Gait disturbances in patients with stroke.  

PubMed

Poststroke hemiplegic gait is a mixture of deviations and compensatory motion dictated by residual functions, and thus each patient must be examined and his/her unique gait pattern identified and documented. Quantitative 3-dimensional gait analysis is the best way to understand the complex multifactorial gait dysfunction in hemiparetic patients. The goals of the present work are to (1) review the temporospatial, kinematic, kinetic, and electromyographic deviations from normal gait that commonly occur after stroke and are of clinical significance, along with the most likely causes of these deviations, and (2) differentiate the departures from normal gait parameters that arise as a direct consequence of poststroke motor problems and those that arise as learned or adaptive compensations for poststroke motor problems. PMID:24451335

Balaban, Birol; Tok, Fatih

2014-07-01

165

Fiducial marker-based correction for involuntary motion in weight-bearing C-arm CT scanning of knees. Part I. Numerical model-based optimization  

PubMed Central

Purpose: Human subjects in standing positions are apt to show much more involuntary motion than in supine positions. The authors aimed to simulate a complicated realistic lower body movement using the four-dimensional (4D) digital extended cardiac-torso (XCAT) phantom. The authors also investigated fiducial marker-based motion compensation methods in two-dimensional (2D) and three-dimensional (3D) space. The level of involuntary movement-induced artifacts and image quality improvement were investigated after applying each method. Methods: An optical tracking system with eight cameras and seven retroreflective markers enabled us to track involuntary motion of the lower body of nine healthy subjects holding a squat position at 60° of flexion. The XCAT-based knee model was developed using the 4D XCAT phantom and the optical tracking data acquired at 120 Hz. The authors divided the lower body in the XCAT into six parts and applied unique affine transforms to each so that the motion (6 degrees of freedom) could be synchronized with the optical markers’ location at each time frame. The control points of the XCAT were tessellated into triangles and 248 projection images were created based on intersections of each ray and monochromatic absorption. The tracking data sets with the largest motion (Subject 2) and the smallest motion (Subject 5) among the nine data sets were used to animate the XCAT knee model. The authors defined eight skin control points well distributed around the knees as pseudo-fiducial markers which functioned as a reference in motion correction. Motion compensation was done in the following ways: (1) simple projection shifting in 2D, (2) deformable projection warping in 2D, and (3) rigid body warping in 3D. Graphics hardware accelerated filtered backprojection was implemented and combined with the three correction methods in order to speed up the simulation process. Correction fidelity was evaluated as a function of number of markers used (4–12) and marker distribution in three scenarios. Results: Average optical-based translational motion for the nine subjects was 2.14 mm (±0.69 mm) and 2.29 mm (±0.63 mm) for the right and left knee, respectively. In the representative central slices of Subject 2, the authors observed 20.30%, 18.30%, and 22.02% improvements in the structural similarity (SSIM) index with 2D shifting, 2D warping, and 3D warping, respectively. The performance of 2D warping improved as the number of markers increased up to 12 while 2D shifting and 3D warping were insensitive to the number of markers used. The minimum required number of markers for 2D shifting, 2D warping, and 3D warping was 4–6, 12, and 8, respectively. An even distribution of markers over the entire field of view provided robust performance for all three correction methods. Conclusions: The authors were able to simulate subject-specific realistic knee movement in weight-bearing positions. This study indicates that involuntary motion can seriously degrade the image quality. The proposed three methods were evaluated with the numerical knee model; 3D warping was shown to outperform the 2D methods. The methods are shown to significantly reduce motion artifacts if an appropriate marker setup is chosen. PMID:24007156

Choi, Jang-Hwan; Fahrig, Rebecca; Keil, Andreas; Besier, Thor F.; Pal, Saikat; McWalter, Emily J.; Beaupré, Gary S.; Maier, Andreas

2013-01-01

166

Influence of the instrumented force shoe on gait pattern in patients with osteoarthritis of the knee.  

PubMed

Osteoarthritis (OA) of the knee is associated with alterations in gait. As an alternative to force plates, instrumented force shoes (IFSs) can be used to measure ground reaction forces. This study evaluated the influence of IFS on gait pattern in patients with knee OA. Twenty patients with knee OA walked in a gait laboratory on IFS and control shoes (CSs). An optoelectronic system and force plate were used to perform 3D gait analyses. A comparison of temporal-spatial gait parameters, kinematics, and kinetics was made between IFS and CS. Patients wearing IFS showed a decrease in walking velocity and cadence (8%), unchanged stride length, an increase in stance time (13%), stride time (11%) and step width (14%). No differences were found in knee adduction moment or knee kinematics. Small differences were found in foot and ankle kinematics (2-5°), knee transverse moments (5%), ankle frontal (3%) and sagittal moments (1%) and ground reaction force (1-6%). The gait of patients with knee OA was only mildly influenced by the IFS, due to increased shoe height and weight and a change in sole stiffness. The changes were small compared to normal variation and clinically relevant differences. Importantly, in OA patients no effect was found on the knee adduction moment. PMID:21866409

van den Noort, Josien; van der Esch, Martin; Steultjens, Martijn P; Dekker, Joost; Schepers, Martin; Veltink, Peter H; Harlaar, Jaap

2011-12-01

167

Single-trial classification of gait and point movement preparation from human EEG  

PubMed Central

Neuroimaging studies provide evidence of cortical involvement immediately before and during gait and during gait-related behaviors such as stepping in place or motor imagery of gait. Here we attempt to perform single-trial classification of gait intent from another movement plan (point intent) or from standing in place. Subjects walked naturally from a starting position to a designated ending position, pointed at a designated position from the starting position, or remained standing at the starting position. The 700 ms of recorded electroencephalography (EEG) before movement onset was used for single-trial classification of trials based on action type and direction (left walk, forward walk, right walk, left point, right point, and stand) as well as action type regardless of direction (stand, walk, point). Classification using regularized LDA was performed on a principal components analysis (PCA) reduced feature space composed of coefficients from levels 1 to 9 of a discrete wavelet decomposition using the Daubechies 4 wavelet. We achieved significant classification for all conditions, with errors as low as 17% when averaged across nine subjects. LDA and PCA highly weighted frequency ranges that included movement related potentials (MRPs), with smaller contributions from frequency ranges that included mu and beta idle motor rhythms. Additionally, error patterns suggested a spatial structure to the EEG signal. Future applications of the cortical gait intent signal may include an additional dimension of control for prosthetics, preemptive corrective feedback for gait disturbances, or human computer interfaces (HCI). PMID:23781166

Velu, Priya D.; de Sa, Virginia R.

2013-01-01

168

Gait Analysis Laboratory  

NASA Technical Reports Server (NTRS)

Complete motion analysis laboratory has evolved out of analyzing walking patterns of crippled children at Stanford Children's Hospital. Data is collected by placing tiny electrical sensors over muscle groups of child's legs and inserting step-sensing switches in soles of shoes. Miniature radio transmitters send signals to receiver for continuous recording of abnormal walking pattern. Engineers are working to apply space electronics miniaturization techniques to reduce size and weight of telemetry system further as well as striving to increase signal bandwidth so analysis can be performed faster and more accurately using a mini-computer.

1976-01-01

169

Cerebral Palsy Gait, Clinical Importance  

PubMed Central

ABSTRACT Cerebral palsy refers to a lesion on an immature brain, that determines permanent neurological disorders. Knowing the exact cause of the disease does not alter the treatment management. The etiology is 2-2.5/1000 births and the rate is constant in the last 40-50 years because advances in medical technologies have permitted the survival of smaller and premature new born children. Gait analysis has four directions: kinematics (represents body movements analysis without calculating the forces), kinetics (represents body moments and forces), energy consumption (measured by oximetry), and neuromuscular activity (measured by EMG). Gait analysis can observe specific deviations in a patient, allowing us to be more accurate in motor diagnoses and treatment solutions: surgery intervention, botulinum toxin injection, use of orthosis, physical kinetic therapy, oral medications, baclofen pump. PMID:24790675

TUGUI, Raluca Dana; ANTONESCU, Dinu

2013-01-01

170

Gait dynamics on an inclined walkway  

Microsoft Academic Search

Objective: This paper documents research that quantifies and describes the biomechanics of normal gait on inclined surfaces.Design: Experimental, investigative.Background: It is necessary to walk on inclined surfaces to negotiate the natural and built environments. Little research has been conducted on the biomechanics of normal gait on inclined surfaces.Methods: The gait of 11 healthy male volunteers was measured using a Vicon

Andrew Stuart McIntosh; Karen T. Beatty; Leanne N. Dwan; Deborah R. Vickers

2006-01-01

171

[Fatigue, exertional dyspnea, unsteady gait].  

PubMed

Exertional dyspnea and fatigue dominated the clinical picture of pernicious anemia in a 78 year old man. A disturbed gait indicated concomitant neurologic disorders. A reduced Vitamin B12 level, an abnormal Schillingtest, atrophy of gastric mucosa as well as maturation disturbance of erythrocytes and neutrophils were present as typical signs of the disease. Administration of Cyanocobalamine led to correction of blood values within three weeks. PMID:2814113

Nati, R; Glänzer, K; Tschubel, K; Vetter, H

1989-11-01

172

Polar Bear  

NSDL National Science Digital Library

This site from the World Wildlife Fund (WWF) International provides general information about polar bears as well as data on the movements of two radio-collared bears, along with the ice status, through a series of online maps.

2007-01-01

173

Testing and Lubrication for Single Race Bearings  

SciTech Connect

Three ES and H-compatible lubricants (Environment, Safety and Health) for single race bearing applications and one hybrid-material single race bearings were evaluated and compared against single race bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in stronglink mechanisms since 1974. Hybrid bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, bearings lubricated with titanium carbide (TiC) on the balls, bearings lubricated with sputtered MoS{sub 2} on races and retainers, and bearings lubricated with electrophoretically deposited MoS{sub 2} were evaluated. The bearings were maintained in a preloaded state in bearing cartridges during cycling and vibration tests. Bearings with electrophoretically deposited MoS{sub 2} performed as well as bearings lubricated with Vydax and were the best performing candidate. All candidates were suitable for low preload applications. Bearings with TiC coated balls and bearings lubricated with sputtered MoS{sub 2} on the races and retainers performed well at high preloads, though not as well as bearings lubricated with electrophoretic deposition of MoS{sub 2}. Bearings with silicon nitride balls were not suitable for high preload applications.

Steinhoff, R.G.

1998-03-04

174

The Gait Disorder in Downbeat Nystagmus Syndrome  

PubMed Central

Background Downbeat nystagmus (DBN) is a common form of acquired fixation nystagmus with key symptoms of oscillopsia and gait disturbance. Gait disturbance could be a result of impaired visual feedback due to the involuntary ocular oscillations. Alternatively, a malfunction of cerebellar locomotor control might be involved, since DBN is considered a vestibulocerebellar disorder. Methods Investigation of walking in 50 DBN patients (age 72±11 years, 23 females) and 50 healthy controls (HS) (age 70±11 years, 23 females) using a pressure sensitive carpet (GAITRite). The patient cohort comprised subjects with only ocular motor signs (DBN) and subjects with an additional limb ataxia (DBNCA). Gait investigation comprised different walking speeds and walking with eyes closed. Results In DBN, gait velocity was reduced (p<0.001) with a reduced stride length (p<0.001), increased base of support (p<0.050), and increased double support (p<0.001). Walking with eyes closed led to significant gait changes in both HS and DBN. These changes were more pronounced in DBN patients (p<0.001). Speed-dependency of gait variability revealed significant differences between the subgroups of DBN and DBNCA (p<0.050). Conclusions (I) Impaired visual control caused by involuntary ocular oscillations cannot sufficiently explain the gait disorder. (II) The gait of patients with DBN is impaired in a speed dependent manner. (III) Analysis of gait variability allows distinguishing DBN from DBNCA: Patients with pure DBN show a speed dependency of gait variability similar to that of patients with afferent vestibular deficits. In DBNCA, gait variability resembles the pattern found in cerebellar ataxia. PMID:25140517

Schniepp, Roman; Wuehr, Max; Huth, Sabrina; Pradhan, Cauchy; Schlick, Cornelia; Brandt, Thomas; Jahn, Klaus

2014-01-01

175

The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements  

PubMed Central

Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, André

2012-01-01

176

Optimal Synchronizability of Bearings  

NASA Astrophysics Data System (ADS)

Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with asymmetrically weighted couplings. Accordingly, these networks can exhibit optimal synchronization properties through fine-tuning of the local interaction strength as a function of node degree [Motter, Zhou, and Kurths, Phys. Rev. E 71, 016116 (2005)PLEEE81539-3755]. We show that, in analogy, the synchronizability of bearings can be maximized by counterbalancing the number of contacts and the inertia of their constituting rotor disks through the mass-radius relation, m˜r?, with an optimal exponent ?=?× which converges to unity for a large number of rotors. Under this condition, and regardless of the presence of a long-tailed distribution of disk radii composing the mechanical system, the average participation per disk is maximized and the energy dissipation rate is homogeneously distributed among elementary rotors.

Araújo, N. A. M.; Seybold, H.; Baram, R. M.; Herrmann, H. J.; Andrade, J. S., Jr.

2013-02-01

177

METACHRONAL WAVE GAIT GENERATION FOR HEXAPOD ROBOTS  

E-print Network

the back as the hind leg lifts and is transferred forward as each leg in turn lifts. At its fastest metachronal waves for legged robots can provide these same advantages. In this paper we use the Cyclic Genetic: genetic, robot, hexapod, gait, control, cyclic, metachronal INTRODUCTION Generating gaits is important

Parker, Gary B.

178

Diabetic Foot Biomechanics and Gait Dysfunction  

PubMed Central

Background Diabetic foot complications represent significant morbidity and precede most of the lower extremity amputations performed. Peripheral neuropathy is a frequent complication of diabetes shown to affect gait. Glycosylation of soft tissues can also affect gait. The purpose of this review article is to highlight the changes in gait for persons with diabetes and highlight the effects of glycosylation on soft tissues at the foot–ground interface. Methods PubMed, the Cochrane Library, and EBSCOhost® on-line databases were searched for articles pertaining to diabetes and gait. Bibliographies from relevant manuscripts were also searched. Findings Patients with diabetes frequently exhibit a conservative gait strategy where there is slower walking speed, wider base of gait, and prolonged double support time. Glycosylation affects are observed in the lower extremities. Initially, skin thickness decreases and skin hardness increases; tendons thicken; muscles atrophy and exhibit activation delays; bones become less dense; joints have limited mobility; and fat pads are less thick, demonstrate fibrotic atrophy, migrate distally, and may be stiffer. Interpretation In conclusion, there do appear to be gait changes in patients with diabetes. These changes, coupled with local soft tissue changes from advanced glycosylated end products, also alter a patient’s gait, putting them at risk of foot ulceration. Better elucidation of these changes throughout the entire spectrum of diabetes disease can help design better treatments and potentially reduce the unnecessarily high prevalence of foot ulcers and amputation. PMID:20663446

Wrobel, James S.; Najafi, Bijan

2010-01-01

179

Gait Analysis by High School Students  

ERIC Educational Resources Information Center

Human walking is a complicated motion. Movement scientists have developed various research methods to study gait. This article describes how a high school student collected and analysed high quality gait data in much the same way that movement scientists do, via the recording and measurement of motions with a video analysis tool and via…

Heck, Andre; van Dongen, Caroline

2008-01-01

180

Dual-Task-Related Gait Changes in  

Microsoft Academic Search

Background: Changes in gait patterns due to a simultaneously performed cognitive task have been reported previously and associated with an increased falling risk among older adults. Little is known whether the type of cognitive task performed while walking is important concerning possible gait interference in older fall-prone individuals. Objective: To quantify and compare the effects of two different cognitive tasks

Olivier Beauchet; Véronique Dubost; Régis Gonthier; Reto W. Kressig

2005-01-01

181

The Inhibition of Subchondral Bone Lesions Significantly Reversed the Weight-Bearing Deficit and the Overexpression of CGRP in DRG Neurons, GFAP and Iba-1 in the Spinal Dorsal Horn in the Monosodium Iodoacetate Induced Model of Osteoarthritis Pain  

PubMed Central

Background Chronic pain is the most prominent and disabling symptom of osteoarthritis (OA). Clinical data suggest that subchondral bone lesions contribute to the occurrence of joint pain. The present study investigated the effect of the inhibition of subchondral bone lesions on joint pain. Methods Osteoarthritic pain was induced by an injection of monosodium iodoacetate (MIA) into the rat knee joint. Zoledronic acid (ZOL), a third generation of bisphosphonate, was used to inhibit subchondral bone lesions. Joint histomorphology was evaluated using X-ray micro computed tomography scanning and hematoxylin-eosin staining. The activity of osteoclast in subchondral bone was evaluated using tartrate-resistant acid phosphatase staining. Joint pain was evaluated using weight-bearing asymmetry, the expression of calcitonin gene-related peptide (CGRP) in the dorsal root ganglion (DRG), and spinal glial activation status using glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule-1 (Iba-1) immunofluorescence. Afferent neurons in the DRGs that innervated the joints were identified using retrograde fluorogold labeling. Results MIA injections induced significant histomorphological alterations and joint pain. The inhibition of subchondral bone lesions by ZOL significantly reduced the MIA-induced weight-bearing deficit and overexpression of CGRP in DRG neurons, GFAP and Iba-1 in the spinal dorsal horn at 3 and 6 weeks after MIA injection; however, joint swelling and synovial reaction were unaffected. Conclusions The inhibition of subchondral bone lesions alleviated joint pain. Subchondral bone lesions should be a key target in the management of osteoarthritic joint pain. PMID:24204985

Liu, Ming; Zhao, Xin; Wang, Xiaoqing; Li, Yang; Mao, Yuanqing; Zhu, Zhenan

2013-01-01

182

Average Gait Differential Image Based Human Recognition  

PubMed Central

The difference between adjacent frames of human walking contains useful information for human gait identification. Based on the previous idea a silhouettes difference based human gait recognition method named as average gait differential image (AGDI) is proposed in this paper. The AGDI is generated by the accumulation of the silhouettes difference between adjacent frames. The advantage of this method lies in that as a feature image it can preserve both the kinetic and static information of walking. Comparing to gait energy image (GEI), AGDI is more fit to representation the variation of silhouettes during walking. Two-dimensional principal component analysis (2DPCA) is used to extract features from the AGDI. Experiments on CASIA dataset show that AGDI has better identification and verification performance than GEI. Comparing to PCA, 2DPCA is a more efficient and less memory storage consumption feature extraction method in gait based recognition. PMID:24895648

Chen, Jinyan; Liu, Jiansheng

2014-01-01

183

Average gait differential image based human recognition.  

PubMed

The difference between adjacent frames of human walking contains useful information for human gait identification. Based on the previous idea a silhouettes difference based human gait recognition method named as average gait differential image (AGDI) is proposed in this paper. The AGDI is generated by the accumulation of the silhouettes difference between adjacent frames. The advantage of this method lies in that as a feature image it can preserve both the kinetic and static information of walking. Comparing to gait energy image (GEI), AGDI is more fit to representation the variation of silhouettes during walking. Two-dimensional principal component analysis (2DPCA) is used to extract features from the AGDI. Experiments on CASIA dataset show that AGDI has better identification and verification performance than GEI. Comparing to PCA, 2DPCA is a more efficient and less memory storage consumption feature extraction method in gait based recognition. PMID:24895648

Chen, Jinyan; Liu, Jiansheng

2014-01-01

184

Aerospace applications of magnetic bearings  

NASA Technical Reports Server (NTRS)

Magnetic bearings have traditionally been considered for use in aerospace applications only where performance advantages have been the primary, if not only, consideration. Conventional wisdom has been that magnetic bearings have certain performance advantages which must be traded off against increased weight, volume, electric power consumption, and system complexity. These perceptions have hampered the use of magnetic bearings in many aerospace applications because weight, volume, and power are almost always primary considerations. This paper will review progress on several active aerospace magnetic bearings programs at SatCon Technology Corporation. The magnetic bearing programs at SatCon cover a broad spectrum of applications including: a magnetically-suspended spacecraft integrated power and attitude control system (IPACS), a magnetically-suspended momentum wheel, magnetic bearings for the gas generator rotor of a turboshaft engine, a vibration-attenuating magnetic bearing system for an airborne telescope, and magnetic bearings for the compressor of a space-rated heat pump system. The emphasis of these programs is to develop magnetic bearing technologies to the point where magnetic bearings can be truly useful, reliable, and well tested components for the aerospace community.

Downer, James; Goldie, James; Gondhalekar, Vijay; Hockney, Richard

1994-01-01

185

Cryogenic Magnetic Bearing Test Facility (CMBTF)  

NASA Technical Reports Server (NTRS)

The Cryogenic Magnetic Bearing Test Facility (CMBTF) was designed and built to evaluate compact, lightweight magnetic bearings for use in the SSME's (space shuttle main engine) liquid oxygen and liquid hydrogen turbopumps. State of the art and tradeoff studies were conducted which indicated that a hybrid permanent magnet bias homopolar magnetic bearing design would be smaller, lighter, and much more efficient than conventional industrial bearings. A test bearing of this type was designed for the test rig for use at both room temperature and cryogenic temperature (-320 F). The bearing was fabricated from state-of-the-art materials and incorporated into the CMBTF. Testing at room temperature was accomplished at Avcon's facility. These preliminary tests indicated that this magnetic bearing is a feasible alternative to older bearing technologies. Analyses showed that the hybrid magnetic bearing is one-third the weight, considerably smaller, and uses less power than previous generations of magnetic bearings.

1992-01-01

186

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2010 CFR

... Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not...than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in contact unless designed to...

2010-10-01

187

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2012 CFR

... Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not...than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in contact unless designed to...

2012-10-01

188

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2014 CFR

... Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not...than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in contact unless designed to...

2014-10-01

189

The Impact of Different Types of Assistive Devices on Gait Measures and Safety in Huntington's Disease  

PubMed Central

Background Gait and balance impairments lead to frequent falls and injuries in individuals with Huntington's disease (HD). Assistive devices (ADs) such as canes and walkers are often prescribed to prevent falls, but their efficacy is unknown. We systematically examined the effects of different types of ADs on quantitative gait measures during walking in a straight path and around obstacles. Methods Spatial and temporal gait parameters were measured in 21 subjects with HD as they walked across a GAITRite walkway under 7 conditions (i.e., using no AD and 6 commonly prescribed ADs: a cane, a weighted cane, a standard walker, and a 2, 3 or 4 wheeled walker). Subjects also were timed and observed for number of stumbles and falls while walking around two obstacles in a figure-of-eight pattern. Results Gait measure variability (i.e., coefficient of variation), an indicator of fall risk, was consistently better when using the 4WW compared to other ADs. Subjects also walked the fastest and had the fewest number of stumbles and falls when using the 4WW in the figure-of-eight course. Subjects walked significantly slower using ADs compared to no AD both across the GAITRite and in the figure-of-eight. Measures reflecting gait stability and safety improved with the 4WW but were made worse by some other ADs. PMID:22363511

White, Susan E.; Kostyk, Sandra K.

2012-01-01

190

Complex muscle vibration patterns to induce gait-like lower-limb movements: proof of concept.  

PubMed

Muscle vibrations can induce motor responses and illusions of complex movements. However, inducing gait-like cyclical movements and illusions requires the application of multiple fast alternating vibrations to lower-limb muscles. The objectives were (1) to test the feasibility of delivering complex vibrations in a time-organized manner and (2) to illustrate the possibility of inducing alternate gait-in-place-like movements using these vibrations. Patterns of vibration, produced by 12 vibrators applied bilaterally on the flexor and extensor muscle groups of the lower limbs, were based on normal gait kinematics. We tested 1 s and 2 s cycle patterns of vibration. Vibrator responses were assessed using auto- and crosscorrelations and frequency analyses based on accelerometry measurements, and compared between patterns. High auto- (>0.8) and crosscorrelation (>0.6) coefficients demonstrated a good response by the vibrators to the control signal. Vibrations induced cyclical, low-amplitude stepping-in-place movements that mimicked alternate walking movements with both legs, with 1 s and 2 s cycle durations, in one nondisabled participant and one participant with American Spinal Injury Association Impairment Scale B spinal cord injury standing, relaxed, with body-weight support. Electromechanical vibrators can deliver complex cyclical vibrations and trigger gait-like lower-limb movements. These results warrant the application of these vibration patterns on individuals with sensorimotor impairments to test their potential in gait rehabilitation. PMID:24933722

Duclos, Cyril; Kemlin, Claire; Lazert, David; Gagnon, Dany; Dyer, Joseph-Omer; Forget, Robert

2014-01-01

191

Polar Bear  

USGS Publications Warehouse

Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

Amstrup, S.D.; DeMaster

1988-01-01

192

Robust Gait Recognition by Learning and Exploiting Sub-gait Characteristics  

Microsoft Academic Search

Gait recognition algorithms often perform poorly because of low resolution video sequences, subjective human motion and challenging\\u000a outdoor scenarios. Despite these challenges, gait recognition research is gaining momentum due to increasing demand and more\\u000a possibilities for deployment by the surveillance industry. Therefore every research contribution which significantly improves\\u000a this new biometric is a milestone. We propose a probabilistic sub-gait interpretation

Ibrahim Venkat; Philippe De Wilde

2011-01-01

193

Effects of fast functional electrical stimulation gait training on mechanical recovery in poststroke gait.  

PubMed

Stroke leads to gait impairments that can negatively influence quality of life. Functional electrical stimulation (FES) applied during fast walking (FastFES) is an effective gait rehabilitation strategy that can lead to improvements in gait performance, walking speed and endurance, balance, activity, and participation poststroke. The effect of FastFES gait training on mechanical energy utilization is not well understood. The objective of this study was to test the effects of 12 weeks of FastFES gait training on mechanical recovery indices of poststroke gait. Kinematic data were collected from 11 stroke survivors before and after 12 weeks of FastFES training. Mechanical recovery was calculated from the positive changes in vertical, anterior-posterior, and medial-lateral components of center of mass energy. The average mechanical recovery increased from 34.5% before training to 40.0% after training. The increase was statistically significant (P = 0.014). The average self-selected walking speed increased from 0.4 m/s to 0.7 m/s after the 12-week FastFES training. The results indicate that the subjects were better able to generate and utilize the external mechanical energy of walking after FastFES gait training. FastFES gait training has the capacity to increase the gait speed, improve the mechanical recovery, and reduce the mechanical energy expenditure of stroke survivors when they walk. PMID:21401663

Hakansson, Nils A; Kesar, Trisia; Reisman, Darcy; Binder-Macleod, Stuart; Higginson, Jill S

2011-03-01

194

Effects of Fast Functional Electrical Stimulation Gait Training on Mechanical Recovery in Post-Stroke Gait  

PubMed Central

Stroke leads to gait impairments that can negatively influence quality of life. Functional electrical stimulation (FES) applied during fast walking is an effective gait rehabilitation strategy that can lead to improvements in gait performance, walking speed and endurance, balance, activity, and participation post-stroke. The effect of FastFES gait training on mechanical energy utilization is not well understood. The objective of this study was to test the effects of 12-weeks of FastFES gait training on mechanical recovery indices of post-stroke gait. Kinematic data were collected from 11 stroke survivors before and after 12-weeks of FastFES training. Mechanical recovery was calculated from the positive changes in vertical, anterior-posterior, and medial-lateral components of COM energy. The average mechanical recovery increased from 34.5% before training to 40.0% after training. The increase was statistically significant (p=.014). The average self-selected walking speed increased from 0.4m/s to 0.7m/s after the 12-week FastFES training. The results indicate that the subjects were better able to generate and utilize the external mechanical energy of walking after FastFES gait training. FastFES gait training has the capacity to increase the gait speed, improve the mechanical recovery, and reduce the mechanical energy expenditure of stroke survivors when they walk. PMID:21401663

Hakansson, Nils A.; Kesar, Trisia; Reisman, Darcy; Binder-Macleod, Stuart; Higginson, Jill S.

2011-01-01

195

Design of a robot for gait rehabilitation  

E-print Network

The ability to walk is important for independent living and when this capacity is affected by injury, gait therapy is the traditional approach to re-train the nervous system, to re-build muscle strength, to improve balance, ...

Bosecker, Caitlyn Joyce

2009-01-01

196

Polar Bear  

NSDL National Science Digital Library

In this episode of the Podcast of Life, host Ari Daniel Shapiro relates two close calls with polar bears. Listen as Heather Cray recalls how, dumped by a storm on a small Arctic island without a shotgun, she got an unexpected wake-up call. And when researcher Steve Amstrup accidentally crashed through the roof of a polar bear’s den, no one could predict what happened next. Also included is a Learn More section that provides background information on the scientists recorded in the podcast, lessons, images, and cool facts.

2009-01-01

197

Quantitative gait disturbances in older adults with cognitive impairments.  

PubMed

Gait is a complex motor task, initiated and governed by different areas of the brain. Studies have shown a clear association between gait and cognition. Impairments in both gait and cognition are prevalent in older adults. Older adults with gait impairment have an increased risk of developing cognitive impairments. Those with cognitive impairment often have gait impairments and more falls than cognitively healthy older adults. Recent studies have shown that quantitative gait analysis, particularly performed during dual task conditions, can detect gait deficits that cannot yet be seen by the naked eye, even to a trained specialist. Some studies have shown that such gait disturbances were measurable years before mild cognitive impairment or dementia or walking difficulties were clinically manifest. Quantitative gait analysis can provide early detection of gait and cognitive impairments as well as fall risk. Future quantitative gait studies may help distinguish dementia subtypes in early stages of the diseases. Early detection of gait and cognitive impairments would provide a better understanding of disease pathophysiology and progression. Early detection also allows the timely implementation of interventions with the ultimate goal of improving or maintaining mobility and functional independence for as long as possible. Quantitative gait analysis should be viewed as a clinical tool to aid diagnoses and treatment planning. This review examines the current literature on quantitatively measured gait impairment in older adults with mild cognitive impairment or a dementia subtype. PMID:24050167

Bridenbaugh, Stephanie A; Kressig, Reto W

2014-01-01

198

Gait training facilitates central drive to ankle dorsiflexors in children with cerebral palsy.  

PubMed

Foot drop and toe walking are frequent concerns in children with cerebral palsy. The main underlying cause of these problems is early damage and lack of maturation of the corticospinal tract. In the present study we investigated whether 4 weeks of daily treadmill training with an incline may facilitate corticospinal transmission and improve the control of the ankle joint in children with cerebral palsy. Sixteen children with cerebral palsy (Gross Motor Classification System I:6, II:6, III:4) aged 5-14 years old, were recruited for the study. Evaluation of gait ability and intramuscular coherence was made twice before and twice after training with an interval of 1 month. Gait kinematics were recorded by 3D video analysis during treadmill walking with a velocity chosen by the child at the first evaluation. Foot pressure was measured by force sensitive foot soles during treadmill and over ground walking. EMG-EMG coherence was calculated from two separate electrode recordings placed over the tibialis anterior muscle. Training involved 30 min of walking daily on a treadmill with an incline for 30 days. Gait training was accompanied by significant increases in gait speed, incline on the treadmill, the maximal voluntary dorsiflexion torque, the number and amplitude of toe lifts late in the swing phase during gait and the weight exerted on the heel during the early stance phase of the gait cycle. EMG-EMG coherence in the beta and gamma frequency bands recorded from tibialis anterior muscle increased significantly when compared to coherence before training. The largest changes in coherence with training were observed for children <10 years of age. Importantly, in contrast to training-induced EMG increases, the increase in coherence was maintained at the follow-up measurement 1 month after training. Changes in the strength of coherence in the beta and gamma band were positively correlated with improvements in the subjects' ability to lift the toes in the swing phase. These data show that daily intensive gait training increases beta and gamma oscillatory drive to ankle dorsiflexor motor neurons and that it improves toe lift and heel strike in children with cerebral palsy. We propose that intensive gait training may produce plastic changes in the corticospinal tract, which are responsible for improvements in gait function. PMID:25623137

Willerslev-Olsen, Maria; Petersen, Tue Hvass; Farmer, Simon Francis; Nielsen, Jens Bo

2015-03-01

199

PAGAS: Portable and Accurate Gait Analysis System.  

PubMed

Gait analysis systems are powerful tools in the monitoring and rehabilitation of many health conditions which result in an altered gait (such as Parkinson's disease and rheumatoid arthritis), along with the injury of lower limbs. However, current systems that provide accurate gait monitoring and analysis are large and expensive, and therefore are available only in professional settings. The goal of this research is to develop and test a Portable and Accurate Gait Analysis System, denoted PAGAS, which enables patients to monitor their own gait and track their progress and improvement over time. Moreover, PAGAS will enable therapists to follow the progress of their patients over time without the need for multiple visits required at a rehabilitation facility, thus saving significant healthcare costs. PAGAS includes footswitches and a micro-controller, which connects to an Android Smart-phone using Bluetooth communication. An application on the Smartphone analyzes the raw data to produce temporal gait parameters that are displayed to the user on a graphical user interface. PMID:23365885

Wagner, Rojay; Ganz, Aura

2012-01-01

200

Development and testing of the Gait Assessment and Intervention Tool (G.A.I.T.): A measure of coordinated gait components  

Microsoft Academic Search

Recent neuroscience methods have provided the basis upon which to develop effective gait training methods for recovery of the coordinated components of gait after neural injury. We determined that there was not an existing observational measure that was, at once, adequately comprehensive, scored in an objectively-based manner, and capable of assessing incremental improvements in the coordinated components of gait. Therefore,

J. J. Daly; J. Nethery; J. P. McCabe; I. Brenner; J. Rogers; J. Gansen; K. Butler; R. Burdsall; K. Roenigk; J. Holcomb

2009-01-01

201

Bobbie Bear  

NSDL National Science Digital Library

Using a virtual manipulative, children construct combinations of different colored shirts and pants to help Bobbie Bear, who is planning a vacation and wants to know how many different outfits he will be able to make from these combinations.

Illuminations National Council of Teachers of Mathematics

2009-03-06

202

Effects of obesity on gait pattern in young individuals with Down syndrome.  

PubMed

In individuals with Down syndrome (DS), the prevalence of obesity is widespread; despite this, there are no experimental studies on the effect of obesity on gait strategy in DS individuals. The aim of this study is to assess the clinical gait analysis of a group of obese individuals with DS and a group of nonobese individuals with DS to determine whether obesity produces a different gait pattern in these participants. In addition, although females and males share a similar mass, they are characterized by different fat distribution and/or accumulation; thus, the presence of differences between females and males within the two DS groups was investigated. Gait analysis data of a group of 78 young individuals with DS and 20 normal-weight participants in the 5-18-year age range were considered. Among DS individuals, 40 were classified as obese (obese DS group), whereas 38 were classified as normal weight (nonobese groups). A three-dimensional gait analysis was carried out using an optoelectronic system, force platforms and video recording. Spatiotemporal, kinematic and kinetic parameters were identified and calculated for each participant. Our results show that most of the parameters were similar in the two groups of DS participants; the only differences were in terms of stance duration, longer in the obese DS group and dorsiflexion ability during the swing phase, which was limited in the obese DS group. The two DS groups were significantly different in terms of ankle stiffness (Ka index): both groups were characterized by reduced values compared with the control group, but the obese group presented lower values with respect to nonobese participants. The data showed that females were characterized by significant modifications of gait pattern compared with males in both groups, in particular, at proximal levels, such as the hip and the pelvis. Our findings indicate that the presence of obesity exerts effects on gait pattern in DS individuals and in particular on ankle joint stiffness. These results may have special clinical relevance; the biomechanical comparison of gait in young obese and nonobese DS individuals may provide a basis for developing either specific or common rehabilitative strategies. PMID:25419690

Galli, Manuela; Cimolin, Veronica; Rigoldi, Chiara; Condoluci, Claudia; Albertini, Giorgio

2015-03-01

203

Gait dynamics in Parkinson's disease: Common and distinct behavior among stride length, gait variability, and fractal-like scaling  

NASA Astrophysics Data System (ADS)

Parkinson's disease (PD) is a common, debilitating neurodegenerative disease. Gait disturbances are a frequent cause of disability and impairment for patients with PD. This article provides a brief introduction to PD and describes the gait changes typically seen in patients with this disease. A major focus of this report is an update on the study of the fractal properties of gait in PD, the relationship between this feature of gait and stride length and gait variability, and the effects of different experimental conditions on these three gait properties. Implications of these findings are also briefly described. This update highlights the idea that while stride length, gait variability, and fractal scaling of gait are all impaired in PD, distinct mechanisms likely contribute to and are responsible for the regulation of these disparate gait properties.

Hausdorff, Jeffrey M.

2009-06-01

204

Foil bearings  

NASA Technical Reports Server (NTRS)

The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

Elrod, David A.

1993-01-01

205

Assessing accelerometer based gait features to support gait analysis for people with complex regional pain syndrome  

Microsoft Academic Search

In this paper, we explored the feasibility of analysing gait patterns during the Short Physical Performance Battery test by using an accelerometer to record the movement of the subject. 12 subjects with Complex Regional Pain Syndrome (CRPS) and 10 control subjects were recruited in this study. 21 gait features including temporal, frequency, regularity and symmetric information were extracted from each

Mingjing Yang; Huiru Zheng; Haiying Wang; Sally McClean; Jane Hall; Nigel Harris

2010-01-01

206

Attempt toward a development of aquatic exercise device for gait disorders.  

PubMed

Abstract Purpose: To develop an aquatic exercise device to facilitate locomotive motor output and achieve repetitive physiological gait patterns to improve movement dysfunctions. Methods: A custom designed leg movement apparatus (LMA) consisted of closed 4-linkage mechanisms and one-length changeable link using a spring. Three-dimensional motions and electromyographic (EMG) activities were recorded in eight healthy subjects to evaluate the reproducibility of the physiological gait patterns using the LMA with or without a spring apparatus in water. Results: Using the LMA with a spring apparatus compared to walking in water, the foot trajectories and the time course of the elevation angles in each lower limb joint kinematics were preserved. The time-series of the EMG showed reciprocal modulation between agonist and antagonist muscle groups in the hip and ankle joints. However, the amplitudes of the tibialis anterior muscle in the first half and rectus femoris in the last half of the movement cycle were reduced using the LMA with a spring apparatus. Conclusion: We developed a novel aquatic exercise device to reproduce physiological gait patterns. The LMA with a spring apparatus would be particularly valuable in therapy for movement dysfunctions to facilitate locomotive motor outputs. Implications for Rehabilitation The leg movement apparatus with spring for underwater use (LMA) would be effective gait training to induce the locomotor-like EMG activities. Hydrotherapy with the LMA has advantages over the partial body weight support treadmill training on land with a robotic device; (1) the LMA is electrically and mechanically safe, and (2) the LMA would require self-effort to generate the gait pattern for movement disorders, or also enable passive gait training by the physiotherapists. PMID:24856666

Miyoshi, Tasuku; Komatsu, Fumie; Takagi, Motoki; Kawashima, Noritaka

2014-05-23

207

Gait initiation in children with Rett syndrome.  

PubMed

Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait. PMID:24743294

Isaias, Ioannis Ugo; Dipaola, Mariangela; Michi, Marlies; Marzegan, Alberto; Volkmann, Jens; Rodocanachi Roidi, Marina L; Frigo, Carlo Albino; Cavallari, Paolo

2014-01-01

208

Gait Initiation in Children with Rett Syndrome  

PubMed Central

Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait. PMID:24743294

Isaias, Ioannis Ugo; Dipaola, Mariangela; Michi, Marlies; Marzegan, Alberto; Volkmann, Jens; Rodocanachi Roidi, Marina L.; Frigo, Carlo Albino; Cavallari, Paolo

2014-01-01

209

Planned gait termination in cerebellar ataxias.  

PubMed

This study set out to characterise the pattern of planned gait termination in a sample of patients with cerebellar diseases. The gait termination phase was recorded, using a motion analysis system, in ten patients with primary degenerative cerebellar disease and in ten controls. The subjects were instructed to walk at different gait speeds and to stop in response to an acoustic signal. Time-distance parameters (step length, step width, double support duration, time-to-slow, stopping time, centre of mass velocity and number of steps) and stability index-related parameters (distance between the "extrapolated centre of mass" (XCoM) and centre of pressure (CoP)) were measured at both matched and self-selected gait speeds. At matched speed the patients, compared with the controls, showed a reduced step length, a greater first and second step width and used more steps to stop. At self-selected speed, almost all the parameters differed from those of the controls. Furthermore, the patients showed an increased stability index, suggesting that they need to maintain a "safety margin" between the XCoM and CoP during the gait termination. Patients develop a series of compensatory strategies in order to preserve balance during planned gait termination, e.g. increasing their step width and number of steps. Ataxic patients need to maintain a safety margin in order to avoid instability when stopping. Given the potential risk of falls when stopping, walking ataxic patients may benefit from a rehabilitation treatment focused on preserving and improving their ability to terminate gait safely. PMID:22274811

Conte, Carmela; Serrao, Mariano; Casali, Carlo; Ranavolo, Alberto; Silvia, Mari; Draicchio, Francesco; Di Fabio, Roberto; Monami, Stefano; Padua, Luca; Iavicoli, Sergio; Sandrini, Giorgio; Pierelli, Francesco

2012-12-01

210

Lubrication for high load duplex bearings  

SciTech Connect

Three ES and H-compatible lubricants (Environment, Safety and Health) for high load duplex bearing applications were evaluated and compared against trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon) which is an ozone-depleting solvent. Bearings with Supercritical CO{sub 2} deposition of PTFE extracted from Vydax AR/IPA, bearings with titanium carbide coated balls, and bearings with diamond-like carbon races and retainers were evaluated. Bearings with Supercritical CO{sub 2} deposition of PTFE from Vydax AR/IPA performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax.

Steinhoff, R.G.

1997-08-01

211

Cave Bear  

NSDL National Science Digital Library

Decoding an ancient cave bear. A two-ton, thirteen-foot cave bear, extinct for ten thousand years, has just experienced a rebirth of sorts. From a tooth and a bone, scientists have recovered its entire genetic code.Eddy Rubin, director of the Department of Energy's Joint Genome Institute, says finding genuine cave bear DNA was like looking for a needle in a haystack. The haystack were all the other organisms that were living in the bones and in the tooth of this ancient creature. And the needle was the little bit of the ancient creature's genome DNA, or genes.They used state-of-the-art computer technology to separate the bear genes from the clutter. Jurassic Park fans should note that they can't clone a new cave bear, nor can they recover DNA from creatures as old as the dinosaurs. But they do hope to reconstruct the genetic code of Neanderthals, our closest non-human relatives, to better understand how our own species evolved. This resource contains detailed text description of the research as well as likes for further inquiry.

American Association for the Advancement of Science (; )

2005-08-15

212

Improved Superconducting Magnetic Rotary Bearings  

NASA Technical Reports Server (NTRS)

Improved magnetic rotary bearings designed by exploiting properties of type-II superconducting materials. Depending on design and application, bearing provides fixed or adjustable compensation for lateral vector component of weight or other lateral load on rotor. Allows applied magnetic field to penetrate partially in clusters of field lines, with concomitant establishment of undamped circulating electrical currents within material. Type-II superconductors have critical magnetic fields and critical temperatures greater than type-I superconductors.

Flom, Yury; Royston, James

1992-01-01

213

Relationships of Stroke Patients’ Gait Parameters with Fear of Falling  

PubMed Central

[Purpose] The purpose of this study was to assess the correlation of gait parameters with fear of falling in stroke survivors. [Subjects] In total, 12 patients with stroke participated. [Methods] The subjects performed on a Biodex Gait Trainer 2 for 5?min to evaluate characteristic gait parameters. The kinematic gait parameters measured were gait speed, step cycle, step length, and time on each foot (step symmetry). All the subjects also completed a fall anxiety survey. [Results] Correlations between gait parameters and fear of falling scores were calculated. There was a moderate degree of correlation between fear of falling scores and the step cycle item of gait parameters. [Conclusions] According to our results, the step cycle gait parameter may be related to increased fall anxiety. PMID:25540488

Park, Jin; Yoo, Ingyu

2014-01-01

214

Advancing clinical gait analysis through technology and policy  

E-print Network

Quantitatively analyzing human gait biomechanics will improve our ability to diagnose and treat disability and to measure the effectiveness of assistive devices. Gait analysis is one technology used to analyze walking, but ...

Tan, Junjay

2009-01-01

215

Gait synchronization in Caenorhabditis elegans  

PubMed Central

Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

Yuan, Jinzhou; Raizen, David M.; Bau, Haim H.

2014-01-01

216

Development and decline of upright gait stability.  

PubMed

Upright gait is a peculiar characteristic of humans that requires the ability to manage upper body dynamic balance while walking, despite the perturbations that are generated by movements of the lower limbs. Most of the studies on upright gait stability have compared young adults and the elderly to determine the effects of aging. In other studies, the comparison was between healthy subjects and patients to examine specific pathologies. Fewer researches have also investigated the development of upright gait stability in children. This review discusses these studies in order to provide an overview of this relevant aspect of human locomotion. A clear trend from development to decline of upright gait stability has been depicted across the entire lifespan, from toddlers at first steps to elderly. In old individuals, even if healthy, the deterioration of skeletal muscle, combined with sensorial and cognitive performance, reduces the ability to maintain an upright trunk during walking, increasing the instability and the risk of falls. Further, the pathological causes of altered development or of a sudden loss of gait stability, as well as the environmental influence are investigated. The last part of this review is focused on the control of upper body accelerations during walking, a particularly interesting topic for the recent development of low-cost wearable accelerometers. PMID:24550829

Iosa, Marco; Fusco, Augusto; Morone, Giovanni; Paolucci, Stefano

2014-01-01

217

Development and Decline of Upright Gait Stability  

PubMed Central

Upright gait is a peculiar characteristic of humans that requires the ability to manage upper body dynamic balance while walking, despite the perturbations that are generated by movements of the lower limbs. Most of the studies on upright gait stability have compared young adults and the elderly to determine the effects of aging. In other studies, the comparison was between healthy subjects and patients to examine specific pathologies. Fewer researches have also investigated the development of upright gait stability in children. This review discusses these studies in order to provide an overview of this relevant aspect of human locomotion. A clear trend from development to decline of upright gait stability has been depicted across the entire lifespan, from toddlers at first steps to elderly. In old individuals, even if healthy, the deterioration of skeletal muscle, combined with sensorial and cognitive performance, reduces the ability to maintain an upright trunk during walking, increasing the instability and the risk of falls. Further, the pathological causes of altered development or of a sudden loss of gait stability, as well as the environmental influence are investigated. The last part of this review is focused on the control of upper body accelerations during walking, a particularly interesting topic for the recent development of low-cost wearable accelerometers. PMID:24550829

Iosa, Marco; Fusco, Augusto; Morone, Giovanni; Paolucci, Stefano

2014-01-01

218

Walking speed influences on gait cycle variability.  

PubMed

The purpose of this study was to investigate the influence of walking speed on the amount and structure of the stride-to-stride fluctuations of the gait cycle. Based on previous findings for both walking [Hausdorff JM, Purdon PL, Peng CK, Ladin Z, Wei JY, Goldberger AL. Fractal dynamics of human gait: stability of long-range correlations in stride interval fluctuations. J Appl Physiol 1996;80:1448-57], and running [Jordan K, Challis JH, Newell KM. Long range correlations in the stride interval of running. Gait Posture 2006;24:120-5] it was hypothesized that the fractal nature of human locomotion is a reflection of the attractor dynamics of human locomotion. Female participants walked for 12min trials at 80%, 90%, 100%, 110% and 120% of their preferred walking speed. Eight gait cycle variables were investigated: stride interval and length, step interval and length, and from the vertical ground reaction force profile the impulse, first and second peak forces, and the trough force. Detrended fluctuation analysis (DFA) revealed the presence of long range correlations in all gait cycle variables investigated. Speed related U-shaped functions occurred in five of the eight variables, with the minima of these curves falling between 100% and 110% of the preferred walking speed. These findings are consistent with those previously shown in running studies and support the hypothesis that reduced strength of long range correlations at preferred locomotion speeds is reflective of enhanced stability and adaptability at these speeds. PMID:16982195

Jordan, Kimberlee; Challis, John H; Newell, Karl M

2007-06-01

219

The asymmetric gait toenail unit sign.  

PubMed

The aim of this investigation was to resolve a diagnostic problem and report toenail unit changes attributable to shoe friction that resemble onychomycosis, but that are fungus-negative, and identify common skeletal causes in patients with an asymmetric walking gait. X-ray and clinical feet inspections were performed to evaluate skeletal components that change normal foot biodynamics. Forty-nine patients, all dermatophyte-negative, were reviewed. All patients were those seen in our private practice who demonstrated skeletal and toenail unit abnormalities such as onycholysis, nail bed keratosis resembling distal subungual onychomycosis, nail plate surface abnormalities, distal toe skin keratosis, a diagnostic nail plate shape, as well as several skeletal abnormalities. The clinical abnormalities of the asymmetric gait syndrome include onycholysis, nail bed keratosis, nail plate surface abnormalities, and a diagnostic nail plate shape. By the patient's history, the skeletal findings that were present worsened with age and, in many patients, they were familial. Onychomycosis does not lead to an asymmetric gait nail problem, asymmetric gait toenail does not favor dermatophyte infection, and not all nail dystrophies are the result of an asymmetric walking gait. PMID:23008938

Zaias, Nardo; Rebell, Gerbert; Casal, German; Appel, Jason

2012-01-01

220

Gait analysis with multiple depth cameras.  

PubMed

The gait movement seems simple at first glance, but in reality it is a very complex neural and biomechanical process. In particular, if a person is affected by a disease or an injury, the gait may be modified. To help detecting such change, we propose a new method based on multiple depth cameras. The aim of this paper is to show the possibility to reconstruct the body 3D volume in real time during gait in order to detect a pathological problem related to this movement and eventually improve diagnosis. Preliminary results showed that the system is sensitive to gait change produced by a heel prosthesis (heel cup) inserted in one shoe of subjects walking on a treadmill. The system detected a difference between maximal forward and backward positions of lower limbs for this pathological walk, a difference that was negligible for normal walk. These promising results were obtained with only 3 low cost depth cameras; we therefore believe that such methodology opens a new and affordable way for 3D volumetric gait analysis. PMID:22255770

Auvinet, Edouard; Multon, Franck; Meunier, Jean

2011-01-01

221

Influence of cell phone email use on characteristics of gait  

Microsoft Academic Search

Previously, gait had been considered an automatic and rhythmical movement that uses minimal attentional resources. The relationship between attention and gait has been revealed in recent research. However, in young adults in particular, the influence of using a cell phone – which is used frequently in daily life and considered to require high attentional demands – on gait has not

Shinichi Demura; Masanobu Uchiyama

2009-01-01

222

Computer Algorithms to Characterize Individual Subject EMG Profiles During Gait  

Microsoft Academic Search

Bogey RA, Barnes LA, Perry J. Computer algorithms to characterize individual subject EMG profiles during gait. Arch Phys Med Rehabil 1992;73:835-41. • Three methods of precisely determining onset and cessation times of gait EMG were investigated. Subjects were 24 normal adults and 32 individuals with gait pathologies. Soleus muscle EMG during free speed level walking was obtained with fine wires,

Ross A. Bogey; Lee A. Barnes; Jacquelin Perry

223

Human Odometry Verifies the Symmetry Perspective on Bipedal Gaits  

ERIC Educational Resources Information Center

Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias "cells") required to model them. Primary gaits are characterized by dihedral symmetry, whereas secondary gaits are characterized by a lower, cyclic symmetry. This fact was used in a test of human odometry. Results…

Turvey, M. T.; Harrison, Steven J.; Frank, Till D.; Carello, Claudia

2012-01-01

224

Gait classification in children with cerebral palsy: A systematic review  

Microsoft Academic Search

This systematic review of the literature evaluates the validity of existing classifications of gait deviations in children with cerebral palsy (CP). Numerous efforts have been made to develop classification systems for gait in CP to assist in diagnosis, clinical decision-making and communication. The internal and external validity of gait classifications in 18 studies were examined, including their sampling methods, content

Fiona Dobson; Meg E. Morris; Richard Baker; H. Kerr Graham

2007-01-01

225

Therapeutic effect of functional electrical stimulation-triggered gait training corresponding gait cycle for stroke.  

PubMed

The purpose of this study was to determine the therapeutic effects of functional electrical stimulation (FES) applied to the gluteus medius and tibialis anterior muscles during the gait cycle in individuals with hemiparetic stroke. Eighteen patients who had suffered a stroke were enrolled in this study. The participants were divided into either the gluteus medius and tibialis anterior (GM + TA) training group (n = 9) or the control group (n = 9). The GM + TA group received FES-triggered gait training to the gluteus medius (GM) in the stance phase and the tibialis anterior (TA) in the swing phase for 30 min, 5 session a week over a 6-week period, and control group who received only gait training without FES-triggered for the same duration of time. A foot-switch sensor was used to trigger the device in the stance (GM) and swing (TA) phases of the gait cycle reciprocally. This study measured three types of outcome measures, including spatiotemporal gait parameters, muscles activities, and balance function. After 6 weeks training, there was a significant improvement in gait velocity, cadence, stride length, and gait symmetry in the GM + TA training group compared to the control group. Dynamic balance function was significantly improved in the GM + TA training group compared to the control group. The mean changeable values of the GM was significantly greater strength in the GM + TA training group than the control group. These findings suggest that FES-triggered gait training of the GM in the stance phase and TA in the swing phase may improve the spatiotemporal parameters of gait in persons with hemiparetic stroke. PMID:24973142

Chung, Yijung; Kim, Jung-Hyun; Cha, Yuri; Hwang, Sujin

2014-07-01

226

Bearing monitoring  

Microsoft Academic Search

At Ford Motor Company, thrust bearing in drill motors is often damaged by metal chips. Since the vibration frequency is several Hz only, it is very difficult to use accelerometers to pick up the vibration signals. Under the support of Ford and NASA, we propose to use a piezo film as a sensor to pick up the slow vibrations of

Roger Xu; Mark W. Stevenson; Chiman Kwan; Leonard S. Haynes

2001-01-01

227

Bear Bones  

NSDL National Science Digital Library

An estimated ten million Americans have osteoporosis, an age-related disease in which the bones gradually become brittle and weak. Now, scientists are looking to animals for clues on how to combat this condition. This resource describes the study of sustaining bone strength of hibernating bears.

Science Update

2004-03-08

228

Human gait recognition based on compactness  

NASA Astrophysics Data System (ADS)

Gait recognition is new biological identity technology and widely researched in recent years for its many advantages compared with other biological identity technology. In this paper, we propose a simple but effective feature-compactness for gait recognition. First an improved background subtraction algorithm is used to obtain the silhouettes. Then the compactness is extracted from the images in the gait sequence as the feature vector. In the step of classification, DTW algorithm is adopted to adjust the feature vectors before classifying and two classifiers (NN and ENN) are used as classifiers. Because of the simple features which we choose, it consumes little time for recognition and the results turn out to be encouraging.

Chen, Feng; Jiang, Jie; Zhang, Guangjun

2008-10-01

229

Wireless gyroscope suit for gait stability estimation.  

PubMed

Gait stability is primary in assessing individuals with high risk of falling, particularly the elderly. Custom made self-adjustable wireless gyroscope suit is used as a sensing device to quantify gait stability. A nonlinear time series analysis i.e. maximum Lyapunov exponent (?*) was employed to estimate the short term and long term stability and it is closely related to the ability of human neuro-muscular control system in maintaining gait stability. Experimental analysis and tests validated the efficacy of this novel approach. The results achieved are comparable with the findings of multiple kinematic and dynamic parameters derived from optical motion capture system and force platform which are widely used as gold standard. PMID:22256153

Gouwanda, Darwin; Senanayake, Namal A

2011-01-01

230

Kinematics gait disorder in men with fibromyalgia.  

PubMed

The aim of this study was to assess the kinematics disorder of gait in men with fibromyalgia. We studied 12 male with fibromyalgia and 14 healthy men. Each participant of the study walked five trials along a 18.6-m walkway. Fibromyalgia patients completed a Spanish version of Fibromyalgia Impact Questionnaire. Significant differences between fibromyalgia and control groups were found in velocity, stride length, and cadence. Gait parameters of men affected by fibromyalgia were impaired when compared to those of healthy group due to bradykinesia. According to previous studies to assess gait variables in female patients, the male with fibromyalgia also showed lower values of velocity, cadence, and stride length than healthy group but not reported significant differences in swing, stance, single, or double support phase. PMID:23292191

Heredia-Jimenez, Jose M; Soto-Hermoso, Victor M

2014-01-01

231

An investigation of gait in children with Attention Deficit Hyperactivity Disorder: a case controlled study.  

PubMed

This study aimed to compare the gait of children with ADHD - Combined Type (ADHD-CT) to typically developing (TD) children. Children with ADHD-CT (n=14; mean age 10 years 4 months) and a TD group (n=13; mean age 10 years 9 months) walked at self-selected slow, preferred and fast speed on an electronic walkway system. Participants completed a total of 15 walking trials; 5 trials per walking condition. Groups were matched on age, intellectual functioning, height and weight. In the preferred walking condition, there was no difference in spatio-temporal gait variables between the ADHD-CT and TD control groups. At self-selected fast speed, children with ADHD-CT were faster and walked with a higher cadence. The subtle alterations in gait pattern that may reflect a timing deficit is consistent with previous ADHD motor studies. In addition, this study extends previous studies in characterising the unique gait profile of non-medicated children with ADHD-CT where a diagnosis of autism spectrum disorder has been ruled out. PMID:24837426

Papadopoulos, Nicole; McGinley, Jennifer L; Bradshaw, John L; Rinehart, Nicole J

2014-08-30

232

Periodic gaits for the CMU ambler  

NASA Technical Reports Server (NTRS)

The configuration of the Carnegie Mellon University Ambler, a six legged autonomous walking vehicle for exploring Mars, enables the recovery of a trailing leg past the leading leg to reduce the energy expenditure in terrain interactions. Gaits developed for this unprecedented configuration are described. A stability criterion was developed which ensures stability of the vehicle in the event of failure of any one of the supporting legs. Periodic gaits developed for the Ambler utilize the Ambler's unique abilities, and continuously satisfy the stability criterion.

Mahalingam, Swaminathan; Dwivedi, Suren N.

1989-01-01

233

Gait analysis by high school students  

NASA Astrophysics Data System (ADS)

Human walking is a complicated motion. Movement scientists have developed various research methods to study gait. This article describes how a high school student collected and analysed high quality gait data in much the same way that movement scientists do, via the recording and measurement of motions with a video analysis tool and via electromyography, i.e., the measurement of muscle activity. Physics, biology, and mathematics come together in this practical investigation work at a rather high level. It shows that science learning at school can resemble science practice in research laboratories, provided that students have adequate tools.

Heck, André; van Dongen, Caroline

2008-05-01

234

Development of gait training system powered by pneumatic actuator like human musculoskeletal system.  

PubMed

The purpose of this study was to develop a body weight support gait training system for stroke and spinal cord injury (SCI) patient. This system consists of an orthosis powered by pneumatic McKibben actuators and a piece of equipment of body weight support. The attachment of powered orthosis can be fit to individual subjects with different body size. This powered orthosis is driven by pneumatic McKibben actuators arranged as a pair of agonistic and antagonistic bi-articular muscle models and two pairs of agonistic and antagonistic mono-articular muscle models like the human musculoskeletal system. The body weight support equipment suspends the subject's body in a wire harness, with the body weight is supported continuously by a counterweight. The powered orthosis is attached to the body weight support equipment by a parallel linkage, and its movement of powered orthosis is limited at the sagittal plane. The weight of the powered orthosis is compensated by a parallel linkage with a gas-spring. In this paper, we report the detailed mechanics of this body weight support gait training system and the results of several experiments for evaluating the system. PMID:22275650

Yamamoto, Shin-ichiroh; Shibata, Yoshiyuki; Imai, Shingo; Nobutomo, Tatsuya; Miyoshi, Tasuku

2011-01-01

235

Fluctuation and synchronization of gait intervals and gait force profiles distinguish stages of Parkinson's disease  

NASA Astrophysics Data System (ADS)

We study the effects of Parkinson's disease (PD) on the long-term fluctuation and phase synchronization properties of gait timing (series of interstride intervals) as well as gait force profiles (series characterizing the morphological changes between the steps). We find that the fluctuations in the gait timing are significantly larger for PD patients and early PD patients, who were not treated yet with medication, compared to age-matched healthy controls. Simultaneously, the long-term correlations and the phase synchronization of right and left leg are significantly reduced in both types of PD patients. Surprisingly, long-term correlations of the gait force profiles are relatively weak for treated PD patients and healthy controls, while they are significantly larger for early PD patients. The results support the idea that timing and morphology of recordings obtained from a complex system can contain complementary information.

Bartsch, Ronny; Plotnik, Meir; Kantelhardt, Jan W.; Havlin, Shlomo; Giladi, Nir; Hausdorff, Jeffrey M.

2007-09-01

236

Tooling Converts Stock Bearings To Custom Bearings  

NASA Technical Reports Server (NTRS)

Technique for reworking stock bearings saves time and produces helicopter-rotor bearings ground more precisely. Split tapered ring at one end of threaded bolt expands to hold inside of inner race bearing assembly; nut, at other end of bolt, adjusts amount of spring tension. Piece of hardware grasps bearing firmly without interfering with grinding operation. Operation produces bearing of higher quality than commercially available bearings.

Fleenor, E. N., Jr.

1983-01-01

237

Gait-Based Human Identification Using Appearance Matching  

NASA Astrophysics Data System (ADS)

In this chapter, we present an appearance-based approach for recognizing human gait. Given the gait video of an individual, the images are binarized and the width of the outer contour of the silhouette of that individual is obtained for each image frame. Several gait features are derived from this basic width vector. Temporally ordered sequences of the feature vectors are then used to represent the gait of a person. While matching the feature templates for recognition, dynamic time-warping (DTW), which is a nonlinear time-normalization technique, is used to deal with naturally occurring changes in the walking speeds of individuals. The performance of the proposed method is tested on indoor as well as outdoor gait databases, and the efficacy of different gait features and their noise resilience is studied. The experiments also demonstrate the effect of change in the viewing angle and frame rate of data capture on the accuracy of gait recognition.

Kale, A.; Cuntoor, N.; Yegnanarayana, B.; Rajagopalan, A. N.; Chellappa, R.

238

Gait identification from invisible shadows  

NASA Astrophysics Data System (ADS)

This paper introduces a person identification system that uses as input the shadow images of a walking person, as projected by multiple lights(in this application invisible/infrared lights); the system uses a database of examples of shadows images of a number of people who walk. While it is accepted that personal identification has a higher correct classification rate if views from multiple cameras are used, most systems use only one camera, mainly because (i) Installation in real-world environments is easier, less cameras and no need to synchronize cameras, (ii) Computational cost is reduced. In the proposed system, we obtain the advantages of multiple viewpoints with a single camera and additional light sources. More specific, we install multiple infrared lights to project shadows of a subject on the ground and a camera with an infrared transmitting filter mounted in the ceiling inside of a building. Shadow areas, which are projections of one's body on the ground by multiple lights, can be considered as body areas captured from different viewpoints; thus, the proposed system is able to capture multiple projections of the body from a single camera. We explored in other papers the use of sunproduced shadow for identification of people walking freely in the outdoor. In this paper the application scenario is a system installed at the airport in the areas that precedes the immigration checkpoint. Japan already has health monitoring cameras focused on approaching individuals, to determine their health condition; the here described system would also be installed in such a controlled area with restricted walk corridors of walk and controlled lighting. Gait is a remote biometrics and can provide early warning; on another hand it can be used as corroborating evidence in a multi-modal biometrics system. A database of images including shadows for a set of 28 walking people was collected, and the features extracted from shadow areas by affine moment invariants, after which identification of the subject followed. The experiments using the database show the effectiveness of the proposed method and further prove the superiority of using multiple viewpoints compared to a single viewpoint.

Iwashita, Yumi; Uchino, Koji; Kurazume, Ryo; Stoica, Adrian

2012-06-01

239

Advances In Magnetic Bearings  

NASA Technical Reports Server (NTRS)

NASA technical memorandum reviews state of technology of magnetic bearings, focusing mainly on attractive bearings rather than repulsive, eddy-current, or Lorentz bearings. Attractive bearings offer greater load capacities and preferred for aerospace machinery.

Fleming, David P.

1994-01-01

240

ORIGINAL ARTICLE Prevalence of Specific Gait Abnormalities  

E-print Network

ORIGINAL ARTICLE Prevalence of Specific Gait Abnormalities in Children With Cerebral Palsy Influence of Cerebral Palsy Subtype, Age, and Previous Surgery Tishya A. L. Wren, PhD,* Susan Rethlefsen, PT. These findings provide important information for counsel- ing ambulatory children with cerebral palsy

Valero-Cuevas, Francisco

241

Gait analysis for human identification , N. Cuntoor  

E-print Network

vectors are used for representing a person's gait. We use the dynamic time-warping (DTW) approach. In [4] several ellipses are fit to different parts of the binarized silhouette of a person. Statistical Chennai-600036, India raju@ee.iitm.ernet.in© Department of Computer Science and Engineering, IIT Madras

Kale, Amit

242

A practical gait analysis system using gyroscopes  

Microsoft Academic Search

This study investigated the possibility of using uni-axial gyroscopes to develop a simple portable gait analysis system. Gyroscopes were attached on the skin surface of the shank and thigh segments and the angular velocity for each segment was recorded in each segment. Segment inclinations and knee angle were derived from segment angular velocities. The angular signals from a motion analysis

Kaiyu Tong; Malcolm H Granat

1999-01-01

243

Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation  

E-print Network

An objective in the design of high performance machinery is to minimize weight so magnetic bearings are often designed to operate slightly lower than the magnetic material saturation. Further weight reduction in the bearings requires operation...

Kang, Kyungdae

2011-02-22

244

Comparison of Gait Aspects According to FES Stimulation Position Applied to Stroke Patients  

PubMed Central

[Purpose] This study sought to identify the gait aspects according to the FES stimulation position in stroke patients during gait training. [Subjects and Methods] To perform gait analysis, ten stroke patients were grouped based on 4 types of gait conditions: gait without FES stimulation (non-FES), gait with FES stimulation on the tibialis anterior (Ta), gait with FES stimulation on the tibialis anterior and quadriceps (TaQ), and gait with FES stimulation on the tibialis anterior and gluteus medius (TaGm). [Results] Based on repeated measures analysis of variance of measurements of gait aspects comprised of gait speed, gait cycle, and step length according to the FES stimulation position, the FES stimulation significantly affected gait aspects. [Conclusion] In conclusion, stimulating the tibialis anterior and quadriceps and stimulating the tibialis anterior and gluteus medius are much more effective than stimulating only the tibialis anterior during gait training in stroke patients using FES. PMID:24764634

Mun, Byeong-mu; Kim, Tae-ho; Lee, Jin-hwan; Lim, Jin-youg; Seo, Dong-kwon; Lee, Dong-jin

2014-01-01

245

Gait recognition based on Kinect sensor  

NASA Astrophysics Data System (ADS)

This paper presents gait recognition based on human skeleton and trajectory of joint points captured by Microsoft Kinect sensor. In this paper Two sets of dynamic features are extracted during one gait cycle: the first is Horizontal Distance Features (HDF) that is based on the distances between (Ankles, knees, hands, shoulders), the second set is the Vertical Distance Features (VDF) that provide significant information of human gait extracted from the height to the ground of (hand, shoulder, and ankles) during one gait cycle. Extracting these two sets of feature are difficult and not accurate based on using traditional camera, therefore the Kinect sensor is used in this paper to determine the precise measurements. The two sets of feature are separately tested and then fused to create one feature vector. A database has been created in house to perform our experiments. This database consists of sixteen males and four females. For each individual, 10 videos have been recorded, each record includes in average two gait cycles. The Kinect sensor is used here to extract all the skeleton points, and these points are used to build up the feature vectors mentioned above. K-nearest neighbor is used as the classification method based on Cityblock distance function. Based on the experimental result the proposed method provides 56% as a recognition rate using HDF, while VDF provided 83.5% recognition accuracy. When fusing both of the HDF and VDF as one feature vector, the recognition rate increased to 92%, the experimental result shows that our method provides significant result compared to the existence methods.

Ahmed, Mohammed; Al-Jawad, Naseer; Sabir, Azhin T.

2014-05-01

246

Estimates of circulation and gait change based on a three-dimensional kinematic analysis of flight in cockatiels (Nymphicus hollandicus) and ringed turtle-doves (Streptopelia risoria).  

PubMed

Birds and bats are known to employ two different gaits in flapping flight, a vortex-ring gait in slow flight and a continuous-vortex gait in fast flight. We studied the use of these gaits over a wide range of speeds (1-17 ms(-1)) and transitions between gaits in cockatiels (Nymphicus hollandicus) and ringed turtle-doves (Streptopelia risoria) trained to fly in a recently built, variable-speed wind tunnel. Gait use was investigated via a combination of three-dimensional kinematics and quasi-steady aerodynamic modeling of bound circulation on the distal and proximal portions of the wing. Estimates of lift from our circulation model were sufficient to support body weight at all but the slowest speeds (1 and 3 ms(-1)). From comparisons of aerodynamic impulse derived from our circulation analysis with the impulse estimated from whole-body acceleration, it appeared that our quasi-steady aerodynamic analysis was most accurate at intermediate speeds (5-11 ms(-1)). Despite differences in wing shape and wing loading, both species shifted from a vortex-ring to a continuous-vortex gait at 7 ms(-1). We found that the shift from a vortex-ring to a continuous-vortex gait (i) was associated with a phase delay in the peak angle of attack of the proximal wing section from downstroke into upstroke and (ii) depended on sufficient forward velocity to provide airflow over the wing during the upstroke similar to that during the downstroke. Our kinematic estimates indicated significant variation in the magnitude of circulation over the course the wingbeat cycle when either species used a continuous-vortex gait. This variation was great enough to suggest that both species shifted to a ladder-wake gait as they approached the maximum flight speed (cockatiels 15 ms(-1), doves 17 ms(-1)) that they would sustain in the wind tunnel. This shift in flight gait appeared to reflect the need to minimize drag and produce forward thrust in order to fly at high speed. The ladder-wake gait was also employed in forward and vertical acceleration at medium and fast flight speeds. PMID:11976351

Hedrick, Tyson L; Tobalske, Bret W; Biewener, Andrew A

2002-05-01

247

Gait and upper limb variability in Parkinson's disease patients with and without freezing of gait.  

PubMed

Patients with Parkinson's disease (PD) and freezing of gait (FOG) (freezers) demonstrate high gait variability. The objective of this study was to determine whether freezers display a higher variability of upper limb movements and elucidate if these changes correlate with gait. We were the first group to compare directly objectively measured gait and upper limb movement variability of freezers between freezing episodes. Patients with objectively verified FOG (n = 11) and PD patients without FOG (non-freezers) (n = 11) in a non-randomized medication condition (OFF/ON) were analyzed. Uncued antiphasic finger tapping and forearm diadochokinetic movements were analyzed via three-dimensional ultrasound kinematic measurements. Gait variability of straight gait was assessed using ground reaction forces. Freezers had shorter stride length (p = 0.004) and higher stride length variability (p = 0.005) in the medication OFF condition. Movement variability was not different during finger tapping or diadochokinesia between the groups. There was a trend towards more freezing of the upper limb during finger tapping for the freezers (p = 0.07). Variability in stride length generation and stride timing was not associated with variability of upper limb movement in freezers. Our findings demonstrate that: (1) freezers have a higher spatial gait variability between freezing episodes; (2) freezing-like episodes of the upper limb occur in PD patients, and tend to be more pronounced among freezers than non-freezers for finger tapping; (3) spatial and temporal upper extremity variability is equally affected in freezers and non-freezers in an uncued task. Upper limb freezing is not correlated to lower limb freezing, implicating a different pathophysiology. PMID:24305993

Barbe, Michael T; Amarell, Martin; Snijders, Anke H; Florin, Esther; Quatuor, Eva-Lotte; Schönau, Eckhard; Fink, Gereon R; Bloem, Bastiaan R; Timmermann, Lars

2014-02-01

248

Cryogenic turbopump bearing materials  

NASA Technical Reports Server (NTRS)

Materials used for modern cryogenic turbopump bearings must withstand extreme conditions of loads and speeds under marginal lubrication. Naturally, these extreme conditions tend to limit the bearing life. It is possible to significantly improve the life of these bearings, however, by improving the fatigue and wear resistance of bearing alloys, and improving the strength, liquid oxygen compatibility and lubricating ability of the bearing cage materials. Improved cooling will also help to keep the bearing temperatures low and hence prolong the bearing life.

Bhat, Biliyar N.

1989-01-01

249

The Golden Ratio of Gait Harmony: Repetitive Proportions of Repetitive Gait Phases  

PubMed Central

In nature, many physical and biological systems have structures showing harmonic properties. Some of them were found related to the irrational number ? known as the golden ratio that has important symmetric and harmonic properties. In this study, the spatiotemporal gait parameters of 25 healthy subjects were analyzed using a stereophotogrammetric system with 25 retroreflective markers located on their skin. The proportions of gait phases were compared with ?, the value of which is about 1.6180. The ratio between the entire gait cycle and stance phase resulted in 1.620?±?0.058, that between stance and the swing phase was 1.629?±?0.173, and that between swing and the double support phase was 1.684?±?0.357. All these ratios did not differ significantly from each other (F = 0.870, P = 0.422, repeated measure analysis of variance) or from ? (P = 0.670, 0.820, 0.422, resp., t-tests). The repetitive gait phases of physiological walking were found in turn in repetitive proportions with each other, revealing an intrinsic harmonic structure. Harmony could be the key for facilitating the control of repetitive walking. Harmony is a powerful unifying factor between seemingly disparate fields of nature, including human gait. PMID:23862161

Iosa, Marco; Marchetti, Fabio; Morone, Giovanni; Caltagirone, Carlo; Paolucci, Stefano; Peppe, Antonella

2013-01-01

250

Gait analysis of a radial symmetrical hexapod robot based on parallel mechanisms  

NASA Astrophysics Data System (ADS)

Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height. This paper investigates the performance of a radial symmetrical hexapod robot based on the dexterity of parallel mechanism. Assuming the constraints between the supporting feet and the ground with hinges, the supporting legs and the hexapod body are taken as a parallel mechanism, and each swing leg is regarded as a serial manipulator. The hexapod robot can be considered as a series of hybrid serial-parallel mechanisms while walking on the ground. Locomotion performance can be got by analyzing these equivalent mechanisms. The kinematics of the whole robotic system is established, and the influence of foothold position on the workspace of robot body is analyzed. A new method to calculate the stride length of multi-legged robots is proposed by analyzing the relationship between the workspaces of two adjacent equivalent parallel mechanisms in one gait cycle. Referring to service region and service sphere, weight service sphere and weight service region are put forward to evaluate the dexterity of robot body. The dexterity of single point in workspace and the dexterity distribution in vertical and horizontal projection plane are demonstrated. Simulation shows when the foothold offset goes up to 174 mm, the dexterity of robot body achieves its maximum value 0.1644 in mixed gait. The proposed methods based on parallel mechanisms can be used to calculate the stride length and the dexterity of multi-legged robot, and provide new approach to determine the stride length, body height, footholds in gait planning of multi-legged robot.

Xu, Kun; Ding, Xilun

2014-09-01

251

Autonomous Evolution of Dynamic Gaits with Two Quadruped Robots  

NASA Technical Reports Server (NTRS)

A challenging task that must be accomplished for every legged robot is creating the walking and running behaviors needed for it to move. In this paper we describe our system for autonomously evolving dynamic gaits on two of Sony's quadruped robots. Our evolutionary algorithm runs on board the robot and uses the robot's sensors to compute the quality of a gait without assistance from the experimenter. First we show the evolution of a pace and trot gait on the OPEN-R prototype robot. With the fastest gait, the robot moves at over 10/min/min., which is more than forty body-lengths/min. While these first gaits are somewhat sensitive to the robot and environment in which they are evolved, we then show the evolution of robust dynamic gaits, one of which is used on the ERS-110, the first consumer version of AIBO.

Hornby, Gregory S.; Takamura, Seichi; Yamamoto, Takashi; Fujita, Masahiro

2004-01-01

252

Hamstring and psoas length of crouch gait in cerebral palsy: a comparison with induced crouch gait in age- and sex-matched controls  

PubMed Central

Background Previous studies have shown that hamstring lengths are often not short in patients with cerebral palsy, which raises concerns over the benefits of distal hamstring lengthening in patients with crouch gait. In this study, the authors measured lengths of hamstrings and psoas muscles in normal subjects mimicking crouch gait and compared these with lengths in cerebral palsy patients with crouch gait. Methods Thirty-six patients with cerebral palsy and crouch gait were included in this study, and in addition, 36 age- and sex-matched normal controls were recruited. Hamstring and psoas muscle lengths in patients were evaluated using gait analysis and interactive musculoskeletal modeling software. Muscle lengths were also measured in the normal control group during normal gait and while mimicking crouch gait, and these were compared with those of cerebral palsy patient with crouch gait. Results No significant differences were observed between maximum hamstring (p=0.810) and maximum psoas (p=0.456) lengths of patients and controls mimicking crouch gait. However, patients showed significantly shorter excursions of hamstring (p=0.022) and psoas (p=0.036) muscles than controls, whereas no significant excursion differences were observed between controls during normal gait and mimicking crouch gait. Conclusions Normal controls mimicking crouch gait and cerebral palsy patients with crouch gait demonstrate similar muscle length patterns. However, mimicked crouch gait did not reproduce the excursion pattern shown by patients with crouch gait, which suggests that reduced hamstring and psoas excursion is an innate characteristic of pathologic crouch gait. PMID:23363928

2013-01-01

253

Treatment of Gait Ignition Failure with Ropinirole  

PubMed Central

Gait ignition failure (GIF) is a syndrome characterized by hesitation or inability to initiate gait from a static position. It may occur in a variety of conditions, including normal pressure hydrocephalus, subcortical vascular disease, parkinsonian syndromes and a variety of focal lesions. Previous information on the treatment of GIF has been primarily anecdotal, but there have been a few reports of response to dopamine agonists. We report a 63-year-old man with anoxic encephalopathy who developed GIF nine years after the initial anoxic insult. The patient’s GIF responded robustly, albeit transiently, to ropinirole. MRI was unrevealing, but a positron emission tomography scan showed hypometabolism in the deep frontal ACA/MCA watershed area; this may have disconnected the basal ganglia from the motor cortex and/or interrupted dopaminergic mesocortical transmission. Our understanding of the pathophysiology and the treatment of GIF remains limited, but there may be at least a limited therapeutic role for dopamine agonists. PMID:25360234

Cohen-Oram, Alexis N.; Stewart, Jonathan T.; Bero, Kim; Hoffmann, Michael W.

2014-01-01

254

Treatment of gait ignition failure with ropinirole.  

PubMed

Gait ignition failure (GIF) is a syndrome characterized by hesitation or inability to initiate gait from a static position. It may occur in a variety of conditions, including normal pressure hydrocephalus, subcortical vascular disease, parkinsonian syndromes and a variety of focal lesions. Previous information on the treatment of GIF has been primarily anecdotal, but there have been a few reports of response to dopamine agonists. We report a 63-year-old man with anoxic encephalopathy who developed GIF nine years after the initial anoxic insult. The patient's GIF responded robustly, albeit transiently, to ropinirole. MRI was unrevealing, but a positron emission tomography scan showed hypometabolism in the deep frontal ACA/MCA watershed area; this may have disconnected the basal ganglia from the motor cortex and/or interrupted dopaminergic mesocortical transmission. Our understanding of the pathophysiology and the treatment of GIF remains limited, but there may be at least a limited therapeutic role for dopamine agonists. PMID:25360234

Cohen-Oram, Alexis N; Stewart, Jonathan T; Bero, Kim; Hoffmann, Michael W

2014-10-01

255

Age-related changes in spatial and temporal gait variables  

Microsoft Academic Search

Grabiner PC, Biswas ST, Grabiner MD. Age-related changes in spatial and temporal gait variables. Arch Phys Med Rehabil 2001;82:31-5. Objective: To extend recent findings describing the effect of age on spatial and temporal gait variables. Design: Experimental. Setting: A gait analysis laboratory. Participants: Two experiments with healthy nonfallers were conducted. Experiment 1 included 33 subjects (n = 15, 72.13 ±

Penny C. Grabiner; S. Tina Biswas; Mark D. Grabiner

2001-01-01

256

Gait and postural stability in obese and nonobese prepubertal boys  

Microsoft Academic Search

McGraw B, McClenaghan BA, Williams HG, Dickerson J, Ward DS. Gait and postural stability in obese and nonobese prepubertal boys. Arch Phys Med Rehabil 2000;81:484-9. Objective: To examine differences in gait and postural stability of obese and nonobese prepubertal boys. Design: Percentage of gait cycle in double support was examined to determine significant differences. Postural stability was compared using temporal

Ben McGraw; Bruce A McClenaghan; Harriet G Williams; John Dickerson; Dianne S Ward

2000-01-01

257

Robot Assisted Gait Training With Active Leg Exoskeleton (ALEX)  

Microsoft Academic Search

Gait training of stroke survivors is crucial to facilitate neuromuscular plasticity needed for improvements in functional walking ability. Robot assisted gait training (RAGT) was developed for stroke survivors using active leg exoskeleton (ALEX) and a force-field controller, which uses assist-as-needed paradigm for rehabilitation. In this paradigm undesirable gait motion is resisted and assistance is provided towards desired motion. The force-field

Sai K. Banala; Seok Hun Kim; Sunil K. Agrawal; John P. Scholz

2009-01-01

258

Dynamic principles of gait and their clinical implications.  

PubMed

A healthy gait pattern depends on an array of biomechanical features, orchestrated by the central nervous system for economy and stability. Injuries and other pathologies can alter these features and result in substantial gait deficits, often with detrimental consequences for energy expenditure and balance. An understanding of the role of biomechanics in the generation of healthy gait, therefore, can provide insight into these deficits. This article examines the basic principles of gait from the standpoint of dynamic walking, an approach that combines an inverted pendulum model of the stance leg with a pendulum model of the swing leg and its impact with the ground. The heel-strike at the end of each step has dynamic effects that can contribute to a periodic gait and its passive stability. Biomechanics, therefore, can account for much of the gait pattern, with additional motor inputs that are important for improving economy and stability. The dynamic walking approach can predict the consequences of disruptions to normal biomechanics, and the associated observations can help explain some aspects of impaired gait. This article reviews the basic principles of dynamic walking and the associated experimental evidence for healthy gait and then considers how the principles may be applied to clinical gait pathologies. PMID:20023002

Kuo, Arthur D; Donelan, J Maxwell

2010-02-01

259

Cognitive Contributions to Gait and Falls: Evidence and Implications  

PubMed Central

Dementia and gait impairments often coexist in older adults and patients with neurodegenerative disease. Both conditions represent independent risk factors for falls. The relationship between cognitive function and gait has recently received increasing attention. Gait is no longer considered merely automated motor activity but rather an activity that requires executive function and attention as well as judgment of external and internal cues. In this review, we intend to: (1) summarize and synthesize the experimental, neuropsychological, and neuroimaging evidence that supports the role played by cognition in the control of gait; and (2) briefly discuss the implications deriving from the interplay between cognition and gait. In recent years, the dual task paradigm has been widely used as an experimental method to explore the interplay between gait and cognition. Several neuropsychological investigations have also demonstrated that walking relies on the use of several cognitive domains, including executive-attentional function, visuospatial abilities, and even memory resources. A number of morphological and functional neuroimaging studies have offered additional evidence supporting the relationship between gait and cognitive resources. Based on the findings from 3 lines of studies, it appears that a growing body of evidence indicates a pivotal role of cognition in gait control and fall prevention. The interplay between higher-order neural function and gait has a number of clinical implications, ranging from integrated assessment tools to possible innovative lines of interventions, including cognitive therapy for falls prevention on one hand and walking program for reducing dementia risk on the other. PMID:24132840

Amboni, Marianna; Barone, Paolo; Hausdorff, Jeffrey M.

2014-01-01

260

A portable system with sample rate of 250 Hz for characterization of knee and hip angles in the sagittal plane during gait  

PubMed Central

Background Gait analysis and research have been developed to obtain characteristics of movement patterns of people while walking. However, traditional measuring systems present different drawbacks that reduce their use and application. Among those drawbacks one can find: high price, low sampling frequency and limiting number of steps to be analyzed. Traditional measuring gait systems carry out their measurement at frequencies oscillating between 60 to 100 Hz. It can be argued about the need of higher sampling rates for gait measurements. However small displacements of the knee or hip for example, cannot be seen with low frequencies required a more detailed sampling and higher frequency sampling. Bearing this in mind, in this paper is presented a 250 Hz system based on accelerometers for gait measurement, and the particularities of knee and hip angles during gait are highlighted. Methods The system was designed with a PCI data acquisition card instrumented with an FPGA to achieve a rate sample of 250 Hz. The accelerometers were placed in thighs and legs to calculate the joint angles of hip and knee in the sagittal plane. The angles were estimated using the acceleration polygon method without integrating the acceleration and without filters. Results The gait of thirty healthy people of Mexican phenotype was analyzed over a flat floor free of obstacles. The results showed the gait phases and particularities associated with the walking style and people's laterality; the movement patterns were similar in the thirty persons. Based on the results, the particularities as the maximum amplitude in the angles and the shape in the movement patterns were related to the anthropometry and people phenotype. Conclusions The sampling frequency was essential to record 340 samples in single gait cycle and so registering the gait cycle with its particularities. In this work were recorded an average of 8 to 10 gait cycles, and the results showed variation regarding works carried out in biomechanics laboratories; this variation was related to the method and reference frame used to obtain the joint angles and the accuracy of measurement system. PMID:24684720

2014-01-01

261

Gait patterns for crime fighting: statistical evaluation  

NASA Astrophysics Data System (ADS)

The criminality is omnipresent during the human history. Modern technology brings novel opportunities for identification of a perpetrator. One of these opportunities is an analysis of video recordings, which may be taken during the crime itself or before/after the crime. The video analysis can be classed as identification analyses, respectively identification of a person via externals. The bipedal locomotion focuses on human movement on the basis of their anatomical-physiological features. Nowadays, the human gait is tested by many laboratories to learn whether the identification via bipedal locomotion is possible or not. The aim of our study is to use 2D components out of 3D data from the VICON Mocap system for deep statistical analyses. This paper introduces recent results of a fundamental study focused on various gait patterns during different conditions. The study contains data from 12 participants. Curves obtained from these measurements were sorted, averaged and statistically tested to estimate the stability and distinctiveness of this biometrics. Results show satisfactory distinctness of some chosen points, while some do not embody significant difference. However, results presented in this paper are of initial phase of further deeper and more exacting analyses of gait patterns under different conditions.

Sulovská, Kate?ina; B?lašková, Silvie; Adámek, Milan

2013-10-01

262

Gait Signal Analysis with Similarity Measure  

PubMed Central

Human gait decision was carried out with the help of similarity measure design. Gait signal was selected through hardware implementation including all in one sensor, control unit, and notebook with connector. Each gait signal was considered as high dimensional data. Therefore, high dimensional data analysis was considered via heuristic technique such as the similarity measure. Each human pattern such as walking, sitting, standing, and stepping up was obtained through experiment. By the results of the analysis, we also identified the overlapped and nonoverlapped data relation, and similarity measure analysis was also illustrated, and comparison with conventional similarity measure was also carried out. Hence, nonoverlapped data similarity analysis provided the clue to solve the similarity of high dimensional data. Considered high dimensional data analysis was designed with consideration of neighborhood information. Proposed similarity measure was applied to identify the behavior patterns of different persons, and different behaviours of the same person. Obtained analysis can be extended to organize health monitoring system for specially elderly persons. PMID:25110724

Shin, Seungsoo

2014-01-01

263

Gait correlation analysis based human identification.  

PubMed

Human gait identification aims to identify people by a sequence of walking images. Comparing with fingerprint or iris based identification, the most important advantage of gait identification is that it can be done at a distance. In this paper, silhouette correlation analysis based human identification approach is proposed. By background subtracting algorithm, the moving silhouette figure can be extracted from the walking images sequence. Every pixel in the silhouette has three dimensions: horizontal axis (x), vertical axis (y), and temporal axis (t). By moving every pixel in the silhouette image along these three dimensions, we can get a new silhouette. The correlation result between the original silhouette and the new one can be used as the raw feature of human gait. Discrete Fourier transform is used to extract features from this correlation result. Then, these features are normalized to minimize the affection of noise. Primary component analysis method is used to reduce the features' dimensions. Experiment based on CASIA database shows that this method has an encouraging recognition performance. PMID:24592144

Chen, Jinyan

2014-01-01

264

Evaluating alternative gait strategies using evolutionary robotics  

PubMed Central

Evolutionary robotics is a branch of artificial intelligence concerned with the automatic generation of autonomous robots. Usually the form of the robot is predefined and various computational techniques are used to control the machine's behaviour. One aspect is the spontaneous generation of walking in legged robots and this can be used to investigate the mechanical requirements for efficient walking in bipeds. This paper demonstrates a bipedal simulator that spontaneously generates walking and running gaits. The model can be customized to represent a range of hominoid morphologies and used to predict performance parameters such as preferred speed and metabolic energy cost. Because it does not require any motion capture data it is particularly suitable for investigating locomotion in fossil animals. The predictions for modern humans are highly accurate in terms of energy cost for a given speed and thus the values predicted for other bipeds are likely to be good estimates. To illustrate this the cost of transport is calculated for Australopithecus afarensis. The model allows the degree of maximum extension at the knee to be varied causing the model to adopt walking gaits varying from chimpanzee-like to human-like. The energy costs associated with these gait choices can thus be calculated and this information used to evaluate possible locomotor strategies in early hominids. PMID:15198699

Sellers, William I; Dennis, Louise A; Wang, W -J; Crompton, Robin H

2004-01-01

265

A simulator study of adverse wear with metal and cement debris contamination in metal-on-metal hip bearings  

PubMed Central

Objectives Third-body wear is believed to be one trigger for adverse results with metal-on-metal (MOM) bearings. Impingement and subluxation may release metal particles from MOM replacements. We therefore challenged MOM bearings with relevant debris types of cobalt–chrome alloy (CoCr), titanium alloy (Ti6Al4V) and polymethylmethacrylate bone cement (PMMA). Methods Cement flakes (PMMA), CoCr and Ti6Al4V particles (size range 5 µm to 400 µm) were run in a MOM wear simulation. Debris allotments (5 mg) were inserted at ten intervals during the five million cycle (5 Mc) test. Results In a clean test phase (0 Mc to 0.8 Mc), lubricants retained their yellow colour. Addition of metal particles at 0.8 Mc turned lubricants black within the first hour of the test and remained so for the duration, while PMMA particles did not change the colour of the lubricant. Rates of wear with PMMA, CoCr and Ti6Al4V debris averaged 0.3 mm3/Mc, 4.1 mm3/Mc and 6.4 mm3/Mc, respectively. Conclusions Metal particles turned simulator lubricants black with rates of wear of MOM bearings an order of magnitude higher than with control PMMA particles. This appeared to model the findings of black, periarticular joint tissues and high CoCr wear in failed MOM replacements. The amount of wear debris produced during a 500 000-cycle interval of gait was 30 to 50 times greater than the weight of triggering particle allotment, indicating that MOM bearings were extremely sensitive to third-body wear. Cite this article: Bone Joint Res 2015;4:29–37. PMID:25736072

Halim, T.; Clarke, I. C.; Burgett-Moreno, M. D.; Donaldson, T. K.; Savisaar, C.; Bowsher, J. G.

2015-01-01

266

Body mass distribution and gait mechanics in fat-tailed dwarf lemurs (Cheirogaleus medius) and patas monkeys (Erythrocebus patas).  

PubMed

Most quadrupeds walk with lateral sequence (LS) gaits, where hind limb touchdowns are followed by ipsilateral forelimb touchdowns. Primates, however, typically walk with diagonal sequence (DS) gaits, where hind limb touchdowns are followed by contralateral forelimb touchdowns. Because the use of DS gaits is nearly ubiquitous among primates, understanding gait selection in primates is critical to understanding primate locomotor evolution. The Support Polygon Model [Tomita, M., 1967. A study on the movement pattern of four limbs in walking. J. Anthropol. Soc. Nippon 75, 120-146; Rollinson, J., Martin, R.D., 1981. Comparative aspects of primate locomotion, with special reference to arboreal cercopithecines. Symp. Zool. Soc. Lond. 48, 377-427] argues that primates' use of DS gaits stems from a more caudal position of the whole-body center of mass (COM) relative to other mammals. We tested the predictions of the Support Polygon Model by examining the effects of natural and experimental variations in COM position on gait mechanics in two distantly related primates: fat-tailed dwarf lemurs (Cheirogaleus medius) and patas monkeys (Erythrocebus patas). Dwarf lemur experiments compared individuals with and without a greatly enlarged tail (a feature associated with torpor that can be expected to shift the COM caudally). During patas monkey experiments, we experimentally shifted the COM cranially with the use of a weighted belt (7-12% of body mass) positioned above the scapulae. Examination of limb kinematics revealed changes consistent with systematic deviations in COM position. Nevertheless, footfall patterns changed in a direction contrary to the predictions of the Support Polygon Model in the dwarf lemurs and did not change at all in the patas monkey. These results suggest that body mass distribution is unlikely to be the sole determinant of footfall pattern in primates and other mammals. PMID:17512970

Young, Jesse W; Patel, Biren A; Stevens, Nancy J

2007-07-01

267

Patient-cooperative control increases active participation of individuals with SCI during robot-aided gait training  

PubMed Central

Background Manual body weight supported treadmill training and robot-aided treadmill training are frequently used techniques for the gait rehabilitation of individuals after stroke and spinal cord injury. Current evidence suggests that robot-aided gait training may be improved by making robotic behavior more patient-cooperative. In this study, we have investigated the immediate effects of patient-cooperative versus non-cooperative robot-aided gait training on individuals with incomplete spinal cord injury (iSCI). Methods Eleven patients with iSCI participated in a single training session with the gait rehabilitation robot Lokomat. The patients were exposed to four different training modes in random order: During both non-cooperative position control and compliant impedance control, fixed timing of movements was provided. During two variants of the patient-cooperative path control approach, free timing of movements was enabled and the robot provided only spatial guidance. The two variants of the path control approach differed in the amount of additional support, which was either individually adjusted or exaggerated. Joint angles and torques of the robot as well as muscle activity and heart rate of the patients were recorded. Kinematic variability, interaction torques, heart rate and muscle activity were compared between the different conditions. Results Patients showed more spatial and temporal kinematic variability, reduced interaction torques, a higher increase of heart rate and more muscle activity in the patient-cooperative path control mode with individually adjusted support than in the non-cooperative position control mode. In the compliant impedance control mode, spatial kinematic variability was increased and interaction torques were reduced, but temporal kinematic variability, heart rate and muscle activity were not significantly higher than in the position control mode. Conclusions Patient-cooperative robot-aided gait training with free timing of movements made individuals with iSCI participate more actively and with larger kinematic variability than non-cooperative, position-controlled robot-aided gait training. PMID:20828422

2010-01-01

268

Force plate analysis of the walking gait in healthy dogs.  

PubMed

Ground reaction forces, impulses, and their relationships to morphometric measurements were evaluated for walking gait in 17 healthy dogs. A force plate was used to record forces at 1-ms intervals. Vertical, craniocaudal, and mediolateral forces were measured and normalized by body weight. Impulses, defined as the total force applied over time, were calculated in vertical and craniocaudal directions. Craniocaudal impulses were further divided into braking and propulsion phases. Braking impulses were significantly greater in the forelimbs (P less than or equal to 0.001), whereas propulsion impulses were generally greater in the hind limbs. Impulses and peak forces were then compared with morphometric measurements (body weight, humeral and femoral lengths, and paw length). All relationships were linear, with correlation coefficients significant (P less than or equal to 0.001). As the size of the dog increased, braking, propulsion and vertical impulses increased. Conversely, as morphometric measurements increased, peak vertical forces decreased. Thus, larger dogs had a lower peak force on each limb, but had a higher total impulse applied during stance phase. As stance phase time increased, peak vertical forces decreased. The results indicated that healthy dogs had significant correlations between ground reaction forces, impulses, and morphometric measurements. PMID:3605807

Budsberg, S C; Verstraete, M C; Soutas-Little, R W

1987-06-01

269

Optimal Synchronizability of Bearings  

E-print Network

Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with ...

Seybold, Hansjorg

270

Lubricant replacement in rolling element bearings for weapon surety devices  

SciTech Connect

Stronglink switches are a weapon surety device that is critical to the nuclear safety theme in modem nuclear weapons. These stronglink switches use rolling element bearings which contain a lubricant consisting of low molecular weight polytetrafluoroethylene (PTFE) fragments. Ozone-depleting solvents are used in both the manufacture and application of this lubricant. An alternate bearing lubrication for stronglink switches is needed that will provide long-term chemical stability, low migration and consistent performance. Candidates that were evaluated include bearings with sputtered MoS{sub 2} on the races and retainers, bearings with TiC-coated balls, and bearings with Si{sub 3}N{sub 4} balls and steel races. These candidates were compared to the lubricants currently used which are bearings lubricated with PTFE fragments of low molecular weight in a fluorocarbon solvent. The candidates were also compared to bearings lubricated with a diester oil which is representative of bearing lubricants used in industrial applications. Evaluation consisted of cycling preloaded bearings and subjecting them to 23 gRMS random vibration. All of the candidates are viable substitutes for low load application where bearing preload is approximately 1 pound. For high load applications where the bearing preload is approximately 10 pounds, bearings with sputtered MoS{sub 2} on the races and retainers appear to be the best substitutes. Bearings with TiC-coated balls also appear to be a viable candidate but these bearings did not perform as well as the sputtered MoS{sub 2}.

Steinhoff, R.; Dugger, M.T.; Varga, K.S. [Sandia National Laboratories, Albuquerque, NM (United States)

1996-05-01

271

Design and test of a magnetic thrust bearing  

NASA Technical Reports Server (NTRS)

A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

1993-01-01

272

A systematic review of the efficacy of gait rehabilitation strategies for spinal cord injury  

PubMed Central

OBJECTIVE To systematically review the evidence for the efficacy of different rehabilitation strategies on functional ambulation following spinal cord injury (SCI). METHODS A keyword literature search of original articles was used to identify published literature evaluating the effectiveness of any treatment or therapy on functional ambulation in people with SCI. The rigor and quality of each study were scored on standardized scales by two independent reviewers. RESULTS The search yielded 160 articles, of which 119 were excluded for not meeting our inclusion criteria. The remaining 41 articles covered various strategies for improving gait: bodyweight supported treadmill training (BWSTT) (n=12), functional electrical stimulation (FES) (n=7), braces/orthoses (n=10), or a combination of these (n=12). There is strong evidence from randomized controlled trials that functional ambulation outcomes following body-weight supported treadmill training (BWSTT) are comparable to an equivalent intensity of overground gait training in sub-acute SCI. In chronic SCI, evidence from pre-test/post-test studies shows that BWSTT may be effective in improving functional ambulation. Pre-test/post-test or post-test only studies provide evidence that FES may augment functional ambulation in sub-acute/chronic SCI while braces may afford particular benefits to people with complete SCI to stand up and ambulate with assistive devices. CONCLUSIONS Rehabilitation strategies that facilitate repeated practice of gait offer the greatest benefits to functional ambulation in sub-acute or chronic SCI. Supportive devices may augment functional ambulation particularly in people with incomplete SCI. PMID:22915835

Lam, Tania; Eng, Janice J; Wolfe, Dalton L; Hsieh, Jane T; Whittaker, Maura

2012-01-01

273

Novel actuation design of a gait trainer with shadow leg approach.  

PubMed

Robotic gait training has developed since the end of the 20(th) century, yet there is much room for improvement in the design of the robots. With the conventional exoskeleton structures, donning of patients in a gait trainer usually is a cumbersome process due to the need of joint alignments and normal walking is often hindered due to obstructed arm swing. Our goal was to design a gait training robots that overcomes these limitations. We propose a novel design in which these drawbacks are reduced to a great amount. By using a parallel structure behind the patient (shadow leg) that is connected to the patient joints with rods, little alignment is needed, the area lateral to the hip is left free, and thus arm swing is not obstructed. The construction is lightweight, because the actuators are mounted on a fixed base and the transmission of power is executed with light weight rods. An end stop in the shadow leg prevents hyper extension of the patient's knee. The relationship between motor displacement and human joint rotations is nonlinear. In this paper we derive the nonlinear relationships between motors and patient joints and verify these. calculations with a measurement. The device has been built, now tests with subjects are required to assess if subjects can indeed walk normally in the robot. PMID:24187188

Meuleman, Jos; Meuleman, Jos; van Asseldonk, Edwin H F; van der Kooij, Herman

2013-06-01

274

Reliability and validity of the Observational Gait Scale in children with spastic diplegia.  

PubMed

The aim of this study was to establish the reliability and validity of visual gait assessment in children with spastic diplegia, who were community or household ambulators, using a modified version of the Physicians Rating Scale, known as the Observational Gait Scale (OGS). Two clinicians viewed edited split-screen video recordings of 20 children/adolescents (11 males, 9 females; mean age 12 years, range 6 to 21 years) made at the time of three-dimensional gait analysis (3-DGA). Walking ability in each child was scored at initial assessment and reassessed from the same videos three months later using the first seven sections of the OGS. Validity of the OGS score was determined by comparison with 3-DGA. The OGS was found to have acceptable interrater and intrarater reliability for knee and foot position in mid-stance, initial foot contact, and heel rise with weighted kappas (wk) ranging from 0.53 to 0.91 (intrarater) and 0.43 to 0.86 (interrater). Comparison with 3-DGA suggests that these sections might also have high validity(wk range 0.38-0.94). Base of support and hind foot position had lower interrater and intrarater reliabilities (wk 0.29 to 0.71 and wk 0.30 to 0.78 respectively) and were not easily validated by 3-DGA. PMID:12549749

Mackey, Anna H; Lobb, Glenis L; Walt, Sharon E; Stott, N Susan

2003-01-01

275

Musculoskeletal stiffness changes linearly in response to increasing load during walking gait.  

PubMed

Development of biologically inspired exoskeletons to assist soldiers in carrying load is a rapidly expanding field. Understanding how the body modulates stiffness in response to changing loads may inform the development of these exoskeletons and is the purpose of the present study. Seventeen subjects walked on a treadmill at a constant preferred walking velocity while nine different backpack loading conditions ranging from 12.5% to 40% bodyweight (BW) were introduced in an ascending and then descending order. Kinematic data were collected using Optotrak, a 3D motion analysis system, and used to estimate the position of the center of mass (COM). Two different estimates of stiffness were computed for the stance phase of gait. Both measures of stiffness were positively and linearly related to load magnitudes, with the slopes of the relationships being larger for the descending than the ascending conditions. These results indicate that changes in mechanical stiffness brought about in the musculoskeletal system vary systematically during increases in load to ensure that critical kinematic variables measured in a previous publication remain invariant (Caron et al., 2013). Changes in stiffness and other kinematics measured at the 40% BW condition suggest a boundary in which gait stiffness control limit is reached and a new gait pattern is required. Since soldiers are now carrying up to 96% of body weight, the need for research with even heavier loads is warranted. These findings have implications on the development of exoskeletons to assist in carrying loads. PMID:25678200

Caron, Robert R; Lewis, Cara L; Saltzman, Elliot; Wagenaar, Robert C; Holt, Kenneth G

2015-04-13

276

Abnormal joint torque patterns exhibited by chronic stroke subjects while walking with a prescribed physiological gait pattern  

PubMed Central

Background It is well documented that individuals with chronic stroke often exhibit considerable gait impairments that significantly impact their quality of life. While stroke subjects often walk asymmetrically, we sought to investigate whether prescribing near normal physiological gait patterns with the use of the Lokomat robotic gait-orthosis could help ameliorate asymmetries in gait, specifically, promote similar ankle, knee, and hip joint torques in both lower extremities. We hypothesized that hemiparetic stroke subjects would demonstrate significant differences in total joint torques in both the frontal and sagittal planes compared to non-disabled subjects despite walking under normal gait kinematic trajectories. Methods A motion analysis system was used to track the kinematic patterns of the pelvis and legs of 10 chronic hemiparetic stroke subjects and 5 age matched controls as they walked in the Lokomat. The subject's legs were attached to the Lokomat using instrumented shank and thigh cuffs while instrumented footlifters were applied to the impaired foot of stroke subjects to aid with foot clearance during swing. With minimal body-weight support, subjects walked at 2.5 km/hr on an instrumented treadmill capable of measuring ground reaction forces. Through a custom inverse dynamics model, the ankle, knee, and hip joint torques were calculated in both the frontal and sagittal planes. A single factor ANOVA was used to investigate differences in joint torques between control, unimpaired, and impaired legs at various points in the gait cycle. Results While the kinematic patterns of the stroke subjects were quite similar to those of the control subjects, the kinetic patterns were very different. During stance phase, the unimpaired limb of stroke subjects produced greater hip extension and knee flexion torques than the control group. At pre-swing, stroke subjects inappropriately extended their impaired knee, while during swing they tended to abduct their impaired leg, both being typical abnormal torque synergy patterns common to stroke gait. Conclusion Despite the Lokomat guiding stroke subjects through physiologically symmetric kinematic gait patterns, abnormal asymmetric joint torque patterns are still generated. These differences from the control group are characteristic of the hip hike and circumduction strategy employed by stroke subjects. PMID:18761735

Neckel, Nathan D; Blonien, Natalie; Nichols, Diane; Hidler, Joseph

2008-01-01

277

Gaits and Gait Transitions for Legged Robots G. Clark Haynes and Alfred A. Rizzi  

E-print Network

introduce the RiSE platform, a hexapod robot capable of vertical climbing, and discuss how gait transitions are noted in the figure. Fig. 2. RiSE on a carpeted wall. The robot uses clawed feet and leg compliance to adhere to the wall. Leg numbering conventions are noted. from level ground walking to stair climbing

278

Hip contact forces and gait patterns from routine activities  

Microsoft Academic Search

In vivo loads acting at the hip joint have so far only been measured in few patients and without detailed documentation of gait data. Such information is required to test and improve wear, strength and fixation stability of hip implants. Measurements of hip contact forces with instrumented implants and synchronous analyses of gait patterns and ground reaction forces were performed

G Bergmann; G Deuretzbacher; M Heller; F Graichen; A Rohlmann; J Strauss; G. N Duda

2001-01-01

279

Asymmetric Passive Dynamic Walker Used to Examine Gait Rehabilitation Methods  

Microsoft Academic Search

Testing gait rehabilitation devices on humans can be a difficult task, due to the effects of the neurological controls of the human body. This thesis advances the use of a passive dynamic walker (PDW) tuned to have asymmetric gait patterns similar to those with\\u000aphysical impairments to test rehabilitation devices. A passive dynamic walker is a multipendulum system that has

John Sushko

2011-01-01

280

Optimal Gait and Form for Animal Locomotion Kevin Wampler  

E-print Network

for the most efficient shape and motion for an animal, subject to a set of constraints dictated by the lawsOptimal Gait and Form for Animal Locomotion Kevin Wampler Zoran Popovi´c University of Washington Abstract We present a fully automatic method for generating gaits and mor- phologies for legged animal

Washington at Seattle, University of

281

Instrumenting gait with an accelerometer: A system and algorithm examination.  

PubMed

Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required. PMID:25749552

Godfrey, A; Del Din, S; Barry, G; Mathers, J C; Rochester, L

2015-04-01

282

Instrumenting gait with an accelerometer: A system and algorithm examination  

PubMed Central

Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required. PMID:25749552

Godfrey, A.; Del Din, S.; Barry, G.; Mathers, J.C.; Rochester, L.

2015-01-01

283

Dynamic knee loads during gait predict proximal tibial bone distribution  

Microsoft Academic Search

This study tested the validity of the prediction of dynamic knee loads based on gait measurements. The relationship between the predicted loads at the knee and the distribution of bone between the medial and lateral sides of the tibia was examined. The motion and external forces and moments at the knee were measured during gait and a statically determinate muscle

Debra E. Hurwitz; Dale R. Sumner; Thomas P. Andriacchi; David A. Sugar

1998-01-01

284

Can Strength Training Predictably Improve Gait Kinematics? A Pilot  

E-print Network

with spastic diplegia who walk with a crouched gait pattern. Cere- bral palsy (CP) is the most prevalent and Knee Extensor Strengthening on Lower- Extremity Alignment in Cerebral Palsy Diane L. Damiano, Allison S that excessive hip and knee flexion during gait, as frequently seen in ambulatory children with cerebral palsy

Delp, Scott

285

Adaptive impedance control of a robotic orthosis for gait rehabilitation.  

PubMed

Intervention of robotic devices in the field of physical gait therapy can help in providing repetitive, systematic, and economically viable training sessions. Interactive or assist-as-needed (AAN) gait training encourages patient voluntary participation in the robotic gait training process which may aid in rapid motor function recovery. In this paper, a lightweight robotic gait training orthosis with two actuated and four passive degrees of freedom (DOFs) is proposed. The actuated DOFs were powered by pneumatic muscle actuators. An AAN gait training paradigm based on adaptive impedance control was developed to provide interactive robotic gait training. The proposed adaptive impedance control scheme adapts the robotic assistance according to the disability level and voluntary participation of human subjects. The robotic orthosis was operated in two gait training modes, namely, inactive mode and active mode, to evaluate the performance of the proposed control scheme. The adaptive impedance control scheme was evaluated on ten neurologically intact subjects. The experimental results demonstrate that an increase in voluntary participation of human subjects resulted in a decrease of the robotic assistance and vice versa. Further clinical evaluations with neurologically impaired subjects are required to establish the therapeutic efficacy of the adaptive-impedance-control-based AAN gait training strategy. PMID:23193241

Hussain, Shahid; Xie, Sheng Q; Jamwal, Prashant K

2013-06-01

286

Factors Related to Gait Function in Post-stroke Patients  

PubMed Central

[Purpose] Gait function after a stroke is an important factor for determining a patient’s ability to independently perform activities of daily living (ADL). The objective of this study was to elucidate the factors associated with gait function in post-stroke patients. [Subjects] Thirty-nine stroke patients (16 females and 23 males; average age 67.82 ± 10.96?years; post-onset duration: 200.18 ± 27.14 days) participated in this study. [Methods] Their gait function, motor function (Manual Muscle Test [MMT] and Brünnstrom stage), level of cognition (Mini-Mental State Examination score [MMSE], and the Loewenstein Occupational Therapy Cognitive Assessment for the Geriatric Population [LOTCA-G]), and ADL (Korean modified Barthel index [K-MBI]) were assessed. [Results] The degree of gait function showed significant positive correlations with the following variables: MMT of the elbow, knee, ankle and wrist; Brünnstrom stage; MMSE; LOTCA-G subscores except motor praxis; K-MBI. Stepwise linear regression analysis revealed the Brünnstrom stage was the only explanatory variable closely associated with gait level. [Conclusion] Gait function of post-stroke patients was related to motor function, cognition, and ADL. In particular, there is a significant association between gait level and the Brünnstrom stages, reflecting the importance of monitoring the motor recovery of gait function in post-stroke patients. PMID:25540503

Cho, Ki Hun; Lee, Joo Young; Lee, Kun Jae; Kang, Eun Kyoung

2014-01-01

287

Automated detection of gait initiation and termination using wearable sensors.  

PubMed

This paper presents algorithms for detection of gait initiation and termination using wearable inertial measurement units and pressure-sensitive insoles. Body joint angles, joint angular velocities, ground reaction force and center of plantar pressure of each foot are obtained from these sensors and input into supervised machine learning algorithms. The proposed initiation detection method recognizes two events: gait onset (an anticipatory movement preceding foot lifting) and toe-off. The termination detection algorithm segments gait into steps, measures the signals over a buffer at the beginning of each step, and determines whether this measurement belongs to the final step. The approach is validated with 10 subjects at two gait speeds, using within-subject and subject-independent cross-validation. Results show that gait initiation can be detected timely and accurately, with few errors in the case of within-subject cross-validation and overall good performance in subject-independent cross-validation. Gait termination can be predicted in over 80% of trials well before the subject comes to a complete stop. Results also show that the two sensor types are equivalent in predicting gait initiation while inertial measurement units are generally superior in predicting gait termination. Potential use of the algorithms is foreseen primarily with assistive devices such as prostheses and exoskeletons. PMID:23938085

Novak, Domen; Reberšek, Peter; De Rossi, Stefano Marco Maria; Donati, Marco; Podobnik, Janez; Beravs, Tadej; Lenzi, Tommaso; Vitiello, Nicola; Carrozza, Maria Chiara; Munih, Marko

2013-12-01

288

Connectivity of the pedunculopontine nucleus in parkinsonian freezing of gait  

E-print Network

of gait, Parkinson's disease, pedunculopontine nucleus Departments of a Neurosurgery, b Neuroradiology.aziz@nds.ox.ac.uk Received 1 June 2010 accepted 6 June 2010 Introduction Parkinson's disease (PD) is a neurodegenerative move on clinical exami- nation and Unified Parkinson's Disease Rating Scale. Eight patients had PD without gait

Hansen, Peter

289

The biomechanics and motor control of gait in Parkinson disease  

Microsoft Academic Search

Parkinson disease is a progressive neurological condition characterised by hypokinesia (reduced movement), akinesia (absent movement), tremor, rigidity and postural instability. These movement disorders are associated with a slow short-stepped, shuffling gait pattern. Analysis of the biomechanics of gait in response to medication, visual cues, attentional strategies and neurosurgery provides insight into the nature of the motor control deficit in Parkinson

Meg E. Morris; Frances Huxham; Jennifer McGinley; Karen Dodd; Robert Iansek

2001-01-01

290

Silhouette-Based Human Identification from Body Shape and Gait  

Microsoft Academic Search

Our goal is to establish a simple baseline method for human identification based on body shape and gait. This baseline recognition method provides a lower bound against which to evaluate more complicated procedures. We present a viewpoint dependent technique based on template match- ing of body silhouettes. Cyclic gait analysis is performed to extract key frames from a test sequence.

Robert T. Collins; Ralph Gross; Jianbo Shi

2002-01-01

291

Limit cycles and their stability in a passive bipedal gait  

Microsoft Academic Search

It is well-known that a suitably designed unpowered mechanical biped robot can “walk” down an inclined plane with a steady gait. The characteristics of the gait (e.g., velocity, time period, step length) depend on the geometry and the inertial properties of the robot and the slope of the plane. A passive motion has the distinction of being “natural” and is

Ambarish Goswami; Bernard Espiau; Ahmed Keramane

1996-01-01

292

Spatial, temporal and muscle action patterns of Tai Chi gait  

Microsoft Academic Search

This study was to quantitatively characterize the spatial, temporal, and neuromuscular activation patterns of Tai Chi gait (TCG). Ten healthy young subjects were tested. The kinematics of TCG and normal gait (NG) were measured using a marker-based motion analysis system and two biomechanical force plates. Surface electromyography (EMG) was recorded from six left-side muscles: tibialis anterior, soleus, peronaeus longus, rectus

Ge Wu; Wei Liu; Juvena Hitt; Debra Millon

2004-01-01

293

Synchronization of oscillations for machine perception of gaits  

E-print Network

that walking is an innate part of the kinetic structure of the human body. For example, McGeer [49,50] de systems of humans have innate oscillations that form a gait. These observations suggest that systems may perceive gaits by synchronizing an internal oscillating model to observed oscillations. We present

Boyd, Jeffrey E.

294

A Novel Approach to Quantify Time Series Differences of Gait Data Using Attractor Attributes  

PubMed Central

In this paper we introduce a new method to expressly use live/corporeal data in quantifying differences of time series data with an underlying limit cycle attractor; and apply it using an example of gait data. Our intention is to identify gait pattern differences between diverse situations and classify them on group and individual subject levels. First we approximated the limit cycle attractors, from which three measures were calculated: ?M amounts to the difference between two attractors (a measure for the differences of two movements), ?D computes the difference between the two associated deviations of the state vector away from the attractor (a measure for the change in movement variation), and ?F, a combination of the previous two, is an index of the change. As an application we quantified these measures for walking on a treadmill under three different conditions: normal walking, dual task walking, and walking with additional weights at the ankle. The new method was able to successfully differentiate between the three walking conditions. Day to day repeatability, studied with repeated trials approximately one week apart, indicated excellent reliability for ?M (ICCave > 0.73 with no differences across days; p > 0.05) and good reliability for ?D (ICCave ?=? 0.414 to 0.610 with no differences across days; p > 0.05). Based on the ability to detect differences in varying gait conditions and the good repeatability of the measures across days, the new method is recommended as an alternative to expensive and time consuming techniques of gait classification assessment. In particular, the new method is an easy to use diagnostic tool to quantify clinical changes in neurological patients. PMID:23951252

Vieten, Manfred M.; Sehle, Aida; Jensen, Randall L.

2013-01-01

295

Optimality Principles for Model-Based Prediction of Human Gait  

PubMed Central

Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient’s gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like cost functions produced realistic gait, with stance phase knee flexion, as opposed to energy-related cost functions which avoided knee flexion during the stance phase. We conclude that fatigue minimization may be one of the primary optimality principles governing human gait. PMID:20074736

Ackermann, Marko; van den Bogert, Antonie J.

2010-01-01

296

Gait dynamics in Parkinson’s disease: Common and distinct behavior among stride length, gait variability, and fractal-like scaling  

PubMed Central

Parkinson’s disease (PD) is a common, debilitating neurodegenerative disease. Gait disturbances are a frequent cause of disability and impairment for patients with PD. This article provides a brief introduction to PD and describes the gait changes typically seen in patients with this disease. A major focus of this report is an update on the study of the fractal properties of gait in PD, the relationship between this feature of gait and stride length and gait variability, and the effects of different experimental conditions on these three gait properties. Implications of these findings are also briefly described. This update highlights the idea that while stride length, gait variability, and fractal scaling of gait are all impaired in PD, distinct mechanisms likely contribute to and are responsible for the regulation of these disparate gait properties. PMID:19566273

Hausdorff, Jeffrey M.

2009-01-01

297

Imaging: what can it tell us about parkinsonian gait?  

PubMed Central

Functional neuroimaging has provided new tools to study cerebral gait control in Parkinson disease (PD). First, imaging of blood flow functions has identified a supraspinal locomotor network that includes the (frontal) cortex, basal ganglia, brainstem tegmentum and the cerebellum. These studies emphasize also the cognitive and attentional dependency of gait in PD. Furthermore, gait in PD and related syndromes like progressive supranuclear palsy may be associated with dysfunction of the indirect, modulatory prefrontal–subthalamic–pedunculopontine loop of locomotor control. The direct, stereotyped locomotor loop from the primary motor cortex to the spinal cord with rhythmic cerebellar input appears preserved and may contribute to the unflexible gait pattern in parkinsonian gait. Second, neurotransmitter and proteinopathy imaging studies are beginning to unravel novel mechanisms of parkinsonian gait and postural disturbances. Dopamine displacement imaging studies have shown evidence for a mesofrontal dopaminergic shift from a depleted striatum in parkinsonian gait. This may place additional burden on other brain systems mediating attention functions to perform previously automatic motor tasks. For example, our preliminary cholinergic imaging studies suggest significant slowing of gait speed when additional forebrain cholinergic denervation occurs in PD. Cholinergic denervation of the pedunculopontine nucleus and its thalamic projections have been associated with falls and impaired postural control. Deposition of ?-amyloid may represent another non-dopaminergic correlate of gait disturbance in PD. These findings illustrate the emergence of dopamine non-responsive gait problems to reflect the transition from a predominantly hypodopaminergic disorder to a multisystem neurodegenerative disorder involving non-dopaminergic locomotor network structures and pathologies. PMID:24132837

Bohnen, Nicolaas I.; Jahn, Klaus

2013-01-01

298

Powered lower limb orthoses for gait rehabilitation  

PubMed Central

Bodyweight supported treadmill training has become a prominent gait rehabilitation method in leading rehabilitation centers. This type of locomotor training has many functional benefits but the labor costs are considerable. To reduce therapist effort, several groups have developed large robotic devices for assisting treadmill stepping. A complementary approach that has not been adequately explored is to use powered lower limb orthoses for locomotor training. Recent advances in robotic technology have made lightweight powered orthoses feasible and practical. An advantage to using powered orthoses as rehabilitation aids is they allow practice starting, turning, stopping, and avoiding obstacles during overground walking. PMID:16568153

Ferris, Daniel P.; Sawicki, Gregory S.; Domingo, Antoinette

2006-01-01

299

DMRT3 is associated with gait type in Mangalarga Marchador horses, but does not control gait ability.  

PubMed

The Mangalarga Marchador (MM) is a Brazilian horse breed known for a uniquely smooth gait. A recent publication described a mutation in the DMRT3 gene that the authors claim controls the ability to perform lateral patterned gaits (Andersson et al. 2012). We tested 81 MM samples for the DMRT3 mutation using extracted DNA from hair bulbs using a novel RFLP. Horses were phenotypically categorized by their gait type (batida or picada), as recorded by the Brazilian Mangalarga Marchador Breeders Association (ABCCMM). Statistical analysis using the plink toolset (Purcell, 2007) revealed significant association between gait type and the DMRT3 mutation (P = 2.3e-22). Deviation from Hardy-Weinberg equilibrium suggests that selective pressure for gait type is altering allele frequencies in this breed (P = 1.00e-5). These results indicate that this polymorphism may be useful for genotype-assisted selection for gait type within this breed. As both batida and picada MM horses can perform lateral gaits, the DMRT3 mutation is not the only locus responsible for the lateral gait pattern. PMID:25690906

Patterson, L; Staiger, E A; Brooks, S A

2015-04-01

300

Bearings for Your Whirligig  

NSDL National Science Digital Library

Experiment with friction and make bearings for a whirligig! This activity is a nice introduction to friction and bearings and demonstrates why bearings are useful for spinning. A related video show Vollis Simpson, an artist who creates kinetic sculptures and whirligigs, explain how he uses bearings in all of his spinning pieces so that they move smoothly.

Science Musuem of Minnesota

1995-01-01

301

Passive magnetic bearing configurations  

DOEpatents

A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

Post, Richard F. (Walnut Creek, CA)

2011-01-25

302

Getting Your Bearings  

NSDL National Science Digital Library

In this activity, learners explore the concept of friction and how ball bearings reduce friction. Learners investigate different uses for ball bearings, how the design has changed over time to incorporate roller bearings, test friction using marbles, and identify the use of ball bearings in everyday items.

IEEE

2013-08-30

303

Probabilistic Gait Classification in Children with Cerebral Palsy: A Bayesian Approach  

ERIC Educational Resources Information Center

Three-dimensional gait analysis (3DGA) generates a wealth of highly variable data. Gait classifications help to reduce, simplify and interpret this vast amount of 3DGA data and thereby assist and facilitate clinical decision making in the treatment of CP. CP gait is often a mix of several clinically accepted distinct gait patterns. Therefore,…

Van Gestel, Leen; De Laet, Tinne; Di Lello, Enrico; Bruyninckx, Herman; Molenaers, Guy; Van Campenhout, Anja; Aertbelien, Erwin; Schwartz, Mike; Wambacq, Hans; De Cock, Paul; Desloovere, Kaat

2011-01-01

304

Gait Patterns in Hemiplegic Children with Cerebral Palsy: Comparison of Right and Left Hemiplegia  

ERIC Educational Resources Information Center

The aims of this study are to compare quantitatively the gait strategy of the right and left hemiplegic children with Cerebral Palsy (CP) using gait analysis. The gait strategy of 28 right hemiparetic CP (RHG) and 23 left hemiparetic CP (LHG) was compared using gait analysis (spatio-temporal and kinematic parameters) and considering the hemiplegic…

Galli, Manuela; Cimolin, Veronica; Rigoldi, Chiara; Tenore, Nunzio; Albertini, Giorgio

2010-01-01

305

Comparative analysis of the gait disorder of normal pressure hydrocephalus and Parkinson's disease  

Microsoft Academic Search

OBJECTIVESComparative gait analyses in neurological diseases interfering with locomotion are of particular interest, as many hypokinetic gait disorders have the same main features. The aim of the present study was (1) to compare the gait disturbance in normal pressure hydrocephalus and Parkinson's disease; (2) to evaluate which variables of the disturbed gait pattern respond to specific treatment in both diseases;

H Stolze; J P Kuhtz-Buschbeck; H Drücke; K Jöhnk; M Illert; G Deuschl

2001-01-01

306

Gait Rehabilitation Therapy Using Robot Generated Force Fields Applied at the Pelvis  

E-print Network

Gait Rehabilitation Therapy Using Robot Generated Force Fields Applied at the Pelvis ABSTRACT The Robotic Gait Rehabilitation (RGR) Trainer was designed and built to target secondary gait deviations tissue dynamics. KEYWORDS: Force field, robotic gait rehabilitation, pelvis. 1 INTRODUCTION Each year

Mavroidis, Constantinos

307

Gait Patterns in Twins with Cerebral Palsy: Similarities and Development over Time after Multilevel Surgery  

ERIC Educational Resources Information Center

To examine gait patterns and gait quality, 7 twins with cerebral palsy were measured preoperatively and after surgical intervention. The aim was to study differences and/or similarities in gait between twins, the influence of personal characteristics and birth conditions, and to describe the development of gait over time after single event…

van Drongelen, Stefan; Dreher, Thomas; Heitzmann, Daniel W. W.; Wolf, Sebastian I.

2013-01-01

308

Cryogenic foil bearing turbopumps  

NASA Technical Reports Server (NTRS)

Cryogenic foil bearing turbopumps offer high reliability and low cost. The fundamental cryogenic foil bearing technology has been validated in both liquid hydrogen and liquid oxygen. High load capacity, excellent rotor dynamics, and negligible bearing wear after over 100 starts and stops, and over many hours of testing, were observed in both fluids. An experimental liquid hydrogen foil bearing turbopump was also successfully demonstrated. The results indicate excellent stability, high reliability, wide throttle-ability, low bearing cooling flow, and two-phase bearing operability. A liquid oxygen foil bearing turbopump has been built and is being tested at NASA MSFC.

Gu, Alston L.

1993-01-01

309

Rolling-Element Bearings  

NASA Technical Reports Server (NTRS)

Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

Hamrock, B. J.; Anderson, W. J.

1983-01-01

310

Introduction to ball bearings  

NASA Technical Reports Server (NTRS)

The purpose of a ball bearing is to provide a relative positioning and rotational freedom while transmitting a load between two structures, usually a shaft and a housing. For high rotational speeds (e.g., in gyroscope ball bearings) the purpose can be expanded to include rotational freedom with practically no wear in the bearing. This condition can be achieved by separating the bearing parts with a coherent film of fluid known as an elastohydrodynamic film. This film can be maintained not only when the bearing carries the load on a shaft, but also when the bearing is preloaded to position the shaft to within micro- or nano-inch accuracy and stability. Background information on ball bearings is provided, different types of ball bearings and their geometry and kinematics are defined, bearing materials, manufacturing processes, and separators are discussed. It is assumed, for the purposes of analysis, that the bearing carries no load.

Hamrock, B. J.; Dowson, D.

1981-01-01

311

Is gait variability reliable? An assessment of spatio-temporal parameters of gait variability during continuous overground walking.  

PubMed

The assessment of gait variability has become an important indicator for quantifying motor performance. However, the use of treadmills is known to influence the temporal rhythm of gait, while non-continuous (i.e. stop-start) overground walking alters gait variability, leading to erroneous results. Through establishing the "8-walk", an overground walking protocol that allows the collection of a high number of consecutive gait cycles, the aim of this study was to determine the conditions under which gait variability can be assessed reliably. Twelve healthy subjects performed continuous barefoot walking at their preferred speed in a path shaped as an "8". Kinematic data of the dominant foot was collected while subjects walked along the straight 10 m sections of the 8-walk during sessions on two different days. Mean spatio-temporal parameters of gait and gait variability were computed for 10, 20, 30, 40, 50 and 60 consecutive cycles. All mean parameters of gait showed excellent reliability (ICC: 0.88-0.98) with only 10 cycles included in the analysis. However, the reliability of spatial and temporal parameters of gait variability improved with increasing number of cycles (ICC: 0.60-0.90) but levelled-off after 50 consecutive cycles, revealing an inter-day test-retest variability of ? 13%. To reliably assess gait variability and evaluate human motor performance, we propose the collection of at least 50 cycles and the use of an 8-walk protocol, which avoids the limitations of treadmill and non-consecutive walking protocols. PMID:23838361

König, N; Singh, N B; von Beckerath, J; Janke, L; Taylor, W R

2014-01-01

312

High efficiency magnetic bearings  

NASA Technical Reports Server (NTRS)

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.

Studer, Philip A.; Jayaraman, Chaitanya P.; Anand, Davinder K.; Kirk, James A.

1993-01-01

313

A collisional perspective on quadrupedal gait dynamics  

PubMed Central

The analysis of terrestrial locomotion over the past half century has focused largely on strategies of mechanical energy recovery used during walking and running. In contrast, we describe the underlying mechanics of legged locomotion as a collision-like interaction that redirects the centre of mass (CoM). We introduce the collision angle, determined by the angle between the CoM force and velocity vectors, and show by computing the collision fraction, a ratio of actual to potential collision, that the quadrupedal walk and gallop employ collision-reduction strategies while the trot permits greater collisions. We provide the first experimental evidence that a collision-based approach can differentiate quadrupedal gaits and quantify interspecific differences. Furthermore, we show that this approach explains the physical basis of a commonly used locomotion metric, the mechanical cost of transport. Collision angle and collision fraction provide a unifying analysis of legged locomotion which can be applied broadly across animal size, leg number and gait. PMID:21471189

Lee, David V.; Bertram, John E. A.; Anttonen, Jennifer T.; Ros, Ivo G.; Harris, Sarah L.; Biewener, Andrew A.

2011-01-01

314

Cholinergic dysfunction contributes to gait disturbance in early Parkinson's disease.  

PubMed

Gait disturbance is an early feature in Parkinson's disease. Its pathophysiology is poorly understood; however, cholinergic dysfunction may be a non-dopaminergic contributor to gait. Short-latency afferent inhibition is a surrogate measure of cholinergic activity, allowing the contribution of cholinergic dysfunction to gait to be evaluated. We hypothesized that short-latency afferent inhibition would be an independent predictor of gait dysfunction in early Parkinson's disease. Twenty-two participants with Parkinson's disease and 22 age-matched control subjects took part in the study. Gait was measured objectively using an instrumented walkway (GAITRite), and subjects were asked to walk at their preferred speed for 2 min around a 25-m circuit. Spatiotemporal characteristics (speed, stride length, stride time and step width) and gait dynamics (variability described as the within subject standard deviation of: speed, stride time, stride length and step width) were determined. Short-latency afferent inhibition was measured by conditioning motor evoked potentials, elicited by transcranial magnetic stimulation of the motor cortex, with electrical stimuli delivered to the contralateral median nerve at intervals ranging from N20 (predetermined) to N20 + 4 ms. Short-latency afferent inhibition was determined as the percentage difference between test and conditioned response for all intervals and was described as the group mean. Participants were optimally medicated at the time of testing. Participants with Parkinson's disease had significantly reduced gait speed (P = 0.002), stride length (P = 0.008) and stride time standard deviation (P = 0.001). Short-latency afferent inhibition was also significantly reduced in participants with Parkinson's disease (P = 0.004). In participants with Parkinson's disease, but not control subjects, significant associations were found between gait speed, short-latency afferent inhibition, age and postural instability and gait disorder score (Movement Disorders Society Unified Parkinson's Disease Rating Scale) and attention, whereas global cognition and depression were marginally significant. No other gait variables were associated with short-latency afferent inhibition. A multiple hierarchical regression model explored the contribution of short-latency afferent inhibition to gait speed, controlling for age, posture and gait symptoms (Postural Instability and Gait Disorder score-Movement Disorders Society Unified Parkinson's Disease Rating Scale), attention and depression. Regression analysis in participants with Parkinson's disease showed that reduced short-latency afferent inhibition was an independent predictor of slower gait speed, explaining 37% of variability. The final model explained 72% of variability in gait speed with only short-latency afferent inhibition and attention emerging as independent determinants. The results suggest that cholinergic dysfunction may be an important and early contributor to gait dysfunction in Parkinson's disease. The findings also point to the contribution of non-motor mechanisms to gait dysfunction. Our study provides new insights into underlying mechanisms of non-dopaminergic gait dysfunction, and may help to direct future therapeutic approaches. PMID:22961550

Rochester, Lynn; Yarnall, Alison J; Baker, Mark R; David, Rachel V; Lord, Susan; Galna, Brook; Burn, David J

2012-09-01

315

Video-Based Human Motion Estimation by Part-Whole Gait Manifold Learning  

Microsoft Academic Search

\\u000a This chapter presents a general gait representation framework for video-based human motion estimation that involves gait modeling\\u000a at both the whole and part levels. Our goal is to estimate the kinematics of an unknown gait from image sequences taken by\\u000a a single camera. This approach involves two generative models, called the kinematic gait generative model (KGGM) and the visual\\u000a gait

Guoliang Fan; Xin Zhang

316

Improvement of Freezing of Gait in Patients with Parkinson's Disease by Imagining Bicycling  

PubMed Central

Freezing of gait (FOG) is one of the factors that reduce the quality of life in patients with Parkinson's disease (PD). Imagining bicycling before gait start provided improvement in FOG in 2 PD patients. Imagining and mimicking bicycling after the initiation of gait allowed the rhythmic gait to continue without interruption. We suggest that imagining and mimicking bicycling, which are nonexternal cues, could serve as a helpful therapeutic approach for the intractable freezing and interruption of gait of PD patients. PMID:24761145

Kikuchi, Akio; Baba, Toru; Hasegawa, Takafumi; Sugeno, Naoto; Konno, Masatoshi; Miura, Emiko; Oshima, Ryuji; Aoki, Masashi; Takeda, Atsushi

2014-01-01

317

Gait variability and basal ganglia disorders: stride-to-stride variations of gait cycle timing in Parkinson's disease and Huntington's disease  

NASA Technical Reports Server (NTRS)

The basal ganglia are thought to play an important role in regulating motor programs involved in gait and in the fluidity and sequencing of movement. We postulated that the ability to maintain a steady gait, with low stride-to-stride variability of gait cycle timing and its subphases, would be diminished with both Parkinson's disease (PD) and Huntington's disease (HD). To test this hypothesis, we obtained quantitative measures of stride-to-stride variability of gait cycle timing in subjects with PD (n = 15), HD (n = 20), and disease-free controls (n = 16). All measures of gait variability were significantly increased in PD and HD. In subjects with PD and HD, gait variability measures were two and three times that observed in control subjects, respectively. The degree of gait variability correlated with disease severity. In contrast, gait speed was significantly lower in PD, but not in HD, and average gait cycle duration and the time spent in many subphases of the gait cycle were similar in control subjects, HD subjects, and PD subjects. These findings are consistent with a differential control of gait variability, speed, and average gait cycle timing that may have implications for understanding the role of the basal ganglia in locomotor control and for quantitatively assessing gait in clinical settings.

Hausdorff, J. M.; Cudkowicz, M. E.; Firtion, R.; Wei, J. Y.; Goldberger, A. L.

1998-01-01

318

Depressive Symptoms and Gait Dysfunction in the Elderly  

PubMed Central

Objective Assess the association between depressive symptoms (not meeting the criteria for major depression) and gait dysfunction in older adults. Design Cross-sectional study. Setting Einstein Aging Study, a community-based longitudinal aging study. Participants Six hundred ten nondemented and nondepressed community-residing adults age 70 and older. Measurements Depressive symptoms measured using the 15-item Geriatric Depression Scale. To obtain a comprehensive assessment of gait, eight individual quantitative gait parameters were assessed: velocity (cm/s), stride length (cm), cadence (steps/min), swing phase (seconds), stance phase (seconds), double support phase (seconds), stride length variability (SD of stride length), and swing time variability (SD of swing time). Multiple linear regression analysis was applied to study the association of depressive symptoms with gait, adjusting for potential confounders including demographic variables, medical illnesses, and clinical gait abnormalities. Results Increased level of depressive symptoms was associated with worse velocity, stride, and swing time variability. The relationship of the remaining five gait variables with depressive symptoms was not significant in the fully adjusted models. Conclusions Higher levels of depressive symptoms are associated with worse performance in specific quantitative gait variables in community-residing older adults. PMID:21422907

Brandler, Tamar C; Wang, Cuiling; Oh-Park, Mooyeon; Holtzer, Roee; Verghese, Joe

2011-01-01

319

[Gait changes as an early indicator of dementia].  

PubMed

Gait disorders are more common in dementia than in the context of the physiological aging process. Prevalence of dementia-associated gait disturbances depends on the type of dementia and the severity of cognitive impairment. While in vascular dementia gait abnormalities are often clinically apparent at early disease stages, Alzheimer's disease patients usually have stable gait until late disease stages. With up-to-date ''brain-imaging" methods, it has been demonstrated that people suffering from dementia are more dependent on cortical activity in order to maintain gait stability in complex situations. When dysfunction of the frontal or temporal lobes occurs, allocation of these resources may no longer be sufficient. Dual-task paradigms are useful to test such resources. It has been shown in early Alzheimer's disease patients that, if the demand of attention exceeds available capacities, quantitative gait changes occur. Relevant parameters seem to be, e.g., walking speed and stride-time variability. Quantitative assessment of gait dysfunction in dementia may, thus, have the potential to serve as a trait marker. PMID:22278005

Jamour, M; Becker, C; Synofzik, M; Maetzler, W

2012-01-01

320

Spectrum of gait impairments in presymptomatic and symptomatic Huntington's disease.  

PubMed

The purpose of this study was to quantify gait impairments in presymptomatic and symptomatic Huntington's disease (HD) subjects, and examine sensitivity of gait measures. Our sample (n = 65) included presymptomatic mutation carriers (PMC) (n = 15), symptomatic HD subjects (SHD) (n = 30) and healthy controls (n = 20). Participants were requested to walk at their preferred speed on a computerized walkway that recorded spatiotemporal variables. We administered the Unified HD Rating Scale (UHDRS) for PMC and SHD. PMC demonstrated decreased gait velocity (P < 0.01), stride length (P < 0.008), and increased time in double support (P < 0.001); and demonstrated higher variability in stride length (P < 0.01) and step time (P < 0.004) compared with controls. These impairments worsened with increasing disease severity for SHD. Gait impairments were correlated with predicted years to onset in PMC (velocity = -0.65; cadence = -0.70, step time = 0.71) and demonstrated high sensitivity and specificity in distinguishing between controls and mutation carriers. In contrast, UHDRS scores did not reveal impairments in gait and balance. Gait bradykinesia and dynamic balance impairments begin in the presymptomatic stage of HD and continue to worsen in the symptomatic stages. Gait measures are sensitive in differentiating between mutation positive and negative individuals even when impairments were not detected by clinical neurological examination. (c) 2008 Movement Disorder Society. PMID:18412252

Rao, Ashwini K; Muratori, Lisa; Louis, Elan D; Moskowitz, Carol B; Marder, Karen S

2008-06-15

321

Gait and menstrual cycle: ovulating women use sexier gaits and walk slowly ahead of men.  

PubMed

Previous research has demonstrated that women's physical appearance or sexual interest is different across the menstrual cycle. However, the nonverbal behavior of women toward men according to their menstrual cycle has not been previously explored. In this study, the gait of women walking ahead a male confederate was recorded with the help of a spy-camera. The amount of time that women spent walking was the first dependent variable whereas the extent to which the women were perceived to be sexually attractive by two judges was the second dependent variable. Comparisons were performed according to the women's ovulation phase measured with an LH salivary test. Near ovulation, it was found that women walked slower and their gait was subjectively rated as sexier. Such behaviors were interpreted as unconscious desires of women near ovulation to reinforce their attractiveness in order to attract more men and to increase their choice of a partner. PMID:22245227

Guéguen, Nicolas

2012-04-01

322

Concurrent prediction of muscle and tibiofemoral contact forces during treadmill gait.  

PubMed

Detailed knowledge of knee kinematics and dynamic loading is essential for improving the design and outcomes of surgical procedures, tissue engineering applications, prosthetics design, and rehabilitation. This study used publicly available data provided by the "Grand Challenge Competition to Predict in-vivo Knee Loads" for the 2013 American Society of Mechanical Engineers Summer Bioengineering Conference (Fregly et al., 2012, "Grand Challenge Competition to Predict in vivo Knee Loads," J. Orthop. Res., 30, pp. 503-513) to develop a full body, musculoskeletal model with subject specific right leg geometries that can concurrently predict muscle forces, ligament forces, and knee and ground contact forces. The model includes representation of foot/floor interactions and predicted tibiofemoral joint loads were compared to measured tibial loads for two different cycles of treadmill gait. The model used anthropometric data (height and weight) to scale the joint center locations and mass properties of a generic model and then used subject bone geometries to more accurately position the hip and ankle. The musculoskeletal model included 44 muscles on the right leg, and subject specific geometries were used to create a 12 degrees-of-freedom anatomical right knee that included both patellofemoral and tibiofemoral articulations. Tibiofemoral motion was constrained by deformable contacts defined between the tibial insert and femoral component geometries and by ligaments. Patellofemoral motion was constrained by contact between the patellar button and femoral component geometries and the patellar tendon. Shoe geometries were added to the feet, and shoe motion was constrained by contact between three shoe segments per foot and the treadmill surface. Six-axis springs constrained motion between the feet and shoe segments. Experimental motion capture data provided input to an inverse kinematics stage, and the final forward dynamics simulations tracked joint angle errors for the left leg and upper body and tracked muscle length errors for the right leg. The one cycle RMS errors between the predicted and measured tibia contact were 178?N and 168?N for the medial and lateral sides for the first gait cycle and 209?N and 228?N for the medial and lateral sides for the faster second gait cycle. One cycle RMS errors between predicted and measured ground reaction forces were 12?N, 13?N, and 65?N in the anterior-posterior, medial-lateral, and vertical directions for the first gait cycle and 43?N, 15?N, and 96?N in the anterior-posterior, medial-lateral, and vertical directions for the second gait cycle. PMID:24389997

Guess, Trent M; Stylianou, Antonis P; Kia, Mohammad

2014-02-01

323

A robust real-time gait event detection using wireless gyroscope and its application on normal and altered gaits.  

PubMed

Gait events detection allows clinicians and biomechanics researchers to determine timing of gait events, to estimate duration of stance phase and swing phase and to segment gait data. It also aids biomedical engineers to improve the design of orthoses and FES (functional electrical stimulation) systems. In recent years, researchers have resorted to using gyroscopes to determine heel-strike (HS) and toe-off (TO) events in gait cycles. However, these methods are subjected to significant delays when implemented in real-time gait monitoring devices, orthoses, and FES systems. Therefore, the work presented in this paper proposes a method that addresses these delays, to ensure real-time gait event detection. The proposed algorithm combines the use of heuristics and zero-crossing method to identify HS and TO. Experiments involving: (1) normal walking; (2) walking with knee brace; and (3) walking with ankle brace for overground walking and treadmill walking were designed to verify and validate the identified HS and TO. The performance of the proposed method was compared against the established gait detection algorithms. It was observed that the proposed method produced detection rate that was comparable to earlier reported methods and recorded reduced time delays, at an average of 100 ms. PMID:25619613

Gouwanda, Darwin; Gopalai, Alpha Agape

2015-02-01

324

The gait variability index: a new way to quantify fluctuation magnitude of spatiotemporal parameters during gait.  

PubMed

This article describes a conglomerate measure of gait variability based on nine spatiotemporal parameters: the Gait Variability Index (GVI). Concurrent validity, inter-session reliability and minimum detectable change (MDC) were evaluated in 31 patients with Friedreich's Ataxia (FRDA), through comparisons with classically used evaluation tools such as the International Cooperative Ataxia Rating Scale (ICARS). GVI scores for the healthy population were 100.3±8.6 and were significantly reduced in FRDA patients (70.4±7.9). The GVI was correlated with the global ICARS score and was sensitive enough to differentiate between groups of FRDA patients categorized by the Posture and Gait Disturbances sub-score. The GVI was found to have a high inter-session reliability with an intraclass correlation coefficient of 0.91. A MDC of 8.6 points was found necessary to ensure that a change in GVI reflects a true change rather than measurement error. The GVI provides a quantitative measure of variability which behaves well statistically in both HP and patients with FRDA. It can be easily implemented using the supplemental data provided with this article. Complementary work is necessary to strengthen the GVI validation. PMID:23889886

Gouelle, Arnaud; Mégrot, Fabrice; Presedo, Ana; Husson, Isabelle; Yelnik, Alain; Penneçot, Georges-François

2013-07-01

325

Muscle hypertrophy in quadriplegics with combined electrical stimulation and body weight support training.  

PubMed

We describe the analysis of muscle hypertrophy in complete quadriplegics after 6 months of treadmill gait training with neuromuscular electrical stimulation (NMES). We aim to evaluate the effect of treadmill gait training using NMES, with 30-50% body weight relief, on muscle mass. Fifteen quadriplegics were divided into gait (n=8) and control (n=7) groups. The gait group (GG) performed training, associated to partial body weight support, for 6 months, twice a week, for 20 min. Control group (CG) individuals performed only conventional physiotherapy, but did not perform gait training using NMES. Magnetic resonance imaging (MRI) was performed over quadriceps, at the beginning and after 6 months. The MRI was done to determine the average of cross-sectional area of the quadriceps. Moreover, a gray scale was used to separate the muscle from the conjunctive tissue (when the value is closer to 225, there is a higher amount of muscle tissue). After 6 months there was an increase of cross-sectional area in the gait group (from 49.81+/-9.36 to 57.33+/-10.32 cm2; P=0.01), but not in the control group (from 43.60+/-7.56 to 41.65 +/- 9.44 cm2; P=0.17). The gray scale did not show significant differences after 6 months; however, the mean value of the gray scale inside the quadriceps in the gait group increased by 7.7% and in the control group decreased by 11.4%. Treadmill gait associated with NMES was efficient to promove quadriceps muscle hypertrophy in quadriplegics with chronic lesions even when a partial body weight support was provided. PMID:18467933

Carvalho de Abreu, Daniela Cristina; Júnior, Alberto Cliquet; Rondina, Jane Maryan; Cendes, Fernando

2008-06-01

326

Introduction to magnetic bearings  

NASA Technical Reports Server (NTRS)

Multi-axis suspension has several advantages over single axis system, in that it provides control of an object with precision in two or three orthogonal axes. In this report, we discuss the primary use of magnetic-bearing suspension and it's relevance to what was formally known as NASA's Annular Suspension and Pointing System (ASPS). This system is an experimental pointing system with applications for the space shuttle and the space station programs. The objectives behind this magnetic suspension research project are to provide insight to the use of the ASPS configuration, to control the solar panels of the space station. This is important to maintain the correct position of the panels in relation to the sun and orbiting space station for the continuous supply of solar energy. Since the panels are suspended, they can be aligned with minimum outside interference. The approach of using magnetic suspension technology guarantees mechanical isolation since there are no contacting surfaces. This isolation reduces vibration transmission and mechanical wear which in turn extends the life of the payload and of the carrier. It should be noted that ASPS has a high pointing accuracy along the line of 0.01 arc-second. This research will be done in a laboratory setting by incorporating five bearing stations and one motion control station. We will attempt to suspend an object of dead weight similar to that of a solar panel. The long term applications may include deep-space navigation, fire control in weapon systems, and an improved mass transit system.

Skowronski, Lori; Bisese, Anne

1993-01-01

327

Fractal and Multifractal Analysis of Human Gait  

NASA Astrophysics Data System (ADS)

We carried out a fractal and multifractal analysis of human gait time series of young and old individuals, and adults with three illnesses that affect the march: The Parkinson's and Huntington's diseases and the amyotrophic lateral sclerosis (ALS). We obtained cumulative plots of events, the correlation function, the Hurst exponent and the Higuchi's fractal dimension of these time series and found that these fractal markers could be a factor to characterize the march, since we obtained different values of these quantities for youths and adults and they are different also for healthy and ill persons and the most anomalous values belong to ill persons. In other physiological signals there is complexity lost related with the age and the illness, in the case of the march the opposite occurs. The multifractal analysis could be also a useful tool to understand the dynamics of these and other complex systems.

Muñoz-Diosdado, A.; del Río Correa, J. L.; Angulo-Brown, F.

2003-09-01

328

[Spastic gait analysis. Contribution of the motion lab].  

PubMed

Etienne-Jules Marey introduced gait motion analysis at the end of the XIXth century. It was rapidly adopted by clinicians and Charcot used it at the beginning of the XXth century in La Salpêtrière. Motion analysis was widely used after the first optoelectronic system was built by Furné in 1968. The optoelectronic system calculates the orientation of each body segment in the space after the determination of the space co-ordinates of cutaneous markers placed over them. It is particularly useful for spastic gait. Many disturbances of kinematics and kinetics have been described during spastic gait. They are the consequences of spasticity and other motor and sensory deficits of central nervous system lesions. Motion analysis must be coupled with electromyographic recording of spastic muscles activity which, with kinetic analysis, enables distinguishing the mechanisms underlying gait disturbances. Motion analysis provides clinicians with an indispensable tool for understanding spasticity and evaluating therapeutic efficacy. PMID:12746696

Rémy-Néris, O; Bouilland, S; Bussel, B

2003-05-01

329

Effect of gait on formation of thermal environment inside footwear.  

PubMed

In this study, the relationship between the gait condition and foot temperature distributions inside footwear was investigated using subject experiments. Mechanical, physical, and physiological variables such as the foot contact force, landing speed, and metabolic heat generation were also measured. Gait motion measurements showed that a large contact force was concentrated in the small area of the heel at the initial contact and later at the forefoot. A faster gait produced a larger contact force, higher landing velocity, higher skin temperature, and larger metabolism during gait. The temperature at the bottom of the foot increased, and the temperature on the upper side decreased. The metabolic heat generation had a basic impact on the temperature profile, and skin temperatures tended to increase gradually. In addition, high-temperature-elevation regions such as the big toe and heel coincided with regions with high-contact loads, which suggested a relationship between the temperature elevation and contact load. PMID:25766423

Shimazaki, Yasuhiro; Murata, Masaaki

2015-07-01

330

Low Power Shoe Integrated Intelligent Wireless Gait Measurement System  

NASA Astrophysics Data System (ADS)

Gait analysis measurement is a method to assess and identify gait events and the measurements of dynamic, motion and pressure parameters involving the lowest part of the body. This significant analysis is widely used in sports, rehabilitation as well as other health diagnostic towards improving the quality of life. This paper presents a new system empowered by Inertia Measurement Unit (IMU), ultrasonic sensors, piezoceramic sensors array, XBee wireless modules and Arduino processing unit. This research focuses on the design and development of a low power ultra-portable shoe integrated wireless intelligent gait measurement using MEMS and recent microelectronic devices for foot clearance, orientation, error correction, gait events and pressure measurement system. It is developed to be cheap, low power, wireless, real time and suitable for real life in-door and out-door environment.

Wahab, Y.; Mazalan, M.; Bakar, N. A.; Anuar, A. F.; Zainol, M. Z.; Hamzah, F.

2014-04-01

331

A wireless gait analysis system by digital textile sensors.  

PubMed

This paper studies the feasibility of spatio-temporal gait analysis based upon digital textile sensors. Digitized legs and feet patterns of healthy subjects and their relations with spatio-temporal gait parameters were analyzed. In the first experiment, spatio-temporal gait parameters were determined during over ground walking. In the second experiment, predicted running, backward walking, walking up stairs and walking down stairs parameters were determined. From the results of the experiments, it is concluded that, for healthy subjects, the duration of subsequent stride cycles and left/right steps, the estimations of step length, cadence, walking speed, central of pressure and central of mass trajectory, can be obtained by analyzing the digital signals from the textile sensors on pants and socks. These parameters are easily displayed in several different graphs allowing the user to view the parameters during gait. Finally, the digital data are easily to analyze the feature of activity recognition. PMID:19965098

Yang, Chang-Ming; Chou, Chun-Mei; Hu, Jwu-Sheng; Hung, Shu-Hui; Yang, Chang-Hwa; Wu, Chih-Chung; Hsu, Ming-Yang; Yang, Tsi-Lin

2009-01-01

332

Mechanical spin bearings  

NASA Technical Reports Server (NTRS)

A spin bearing assembly including, a pair of mutually opposing complementary bearing support members having mutually spaced apart bearing support surfaces which may be, for example, bearing races and a set of spin bearings located therebetween. Each spin bearing includes a pair of end faces, a central rotational axis passing through the end faces, a waist region substantially mid-way between the end faces and having a first thickness dimension, and discrete side surface regions located between the waist region and the end faces and having a second thickness dimension different from the first thickness dimension of the waist region and wherein the side surface regions further have respective curvilinear contact surfaces adapted to provide a plurality of bearing contact points on the bearing support members.

Vranish, John M. (Inventor)

1998-01-01

333

Tracking Polar Bears  

NSDL National Science Digital Library

In this interactive activity adapted from the USGS Alaska Science Center, track the movements of a polar bear as it migrates across the changing Arctic sea ice and compare the paths of four different polar bears.

2008-01-17

334

Hysteresis in the metachronal-tripod gait transition of insects: A modeling study  

NASA Astrophysics Data System (ADS)

Locomotion in biological systems involves various gaits, and hysteresis appears when the gaits change in accordance with the locomotion speed. That is, the gaits vary at different locomotion speeds depending on the direction of speed change. Although hysteresis is a typical characteristic of nonlinear dynamic systems, the underlying mechanism for the hysteresis in gait transitions remains largely unclear. In this study, we construct a neuromechanical model of an insect and investigate the dynamic characteristics of its gait and gait transition. The simulation results show that our insect model produces metachronal and tripod gaits depending on the locomotion speed through dynamic interactions among the body mechanical system, the nervous system, and the environment in a self-organized manner. They also show that it undergoes the metachronal-tripod gait transition with hysteresis by changing the locomotion speed. We examined the hysteresis mechanism in the metachronal-tripod gait transition of insects from a dynamic viewpoint.

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2013-07-01

335

Polar Bears Change Diet  

NSDL National Science Digital Library

This radio broadcast from 2001 explains how polar bears have adjusted their diet due to the climate warming around Hudson Bay, Canada. The ringed seals that polar bears normally eat have been harder for polar bears to get to, due to disappearing ice. This has forced polar bears to begin eating harbor seals and bearded seals. The clip is 4 minutes and 15 seconds in length.

Doug Schneider

2007-12-12

336

Axial Halbach Magnetic Bearings  

NASA Technical Reports Server (NTRS)

Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

2008-01-01

337

Gait-based person recognition using arbitrary view transformation model.  

PubMed

Gait recognition is a useful biometric trait for person authentication because it is usable even with low image resolution. One challenge is robustness to a view change (cross-view matching); view transformation models (VTMs) have been proposed to solve this. The VTMs work well if the target views are the same as their discrete training views. However, the gait traits are observed from an arbitrary view in a real situation. Thus, the target views may not coincide with discrete training views, resulting in recognition accuracy degradation. We propose an arbitrary VTM (AVTM) that accurately matches a pair of gait traits from an arbitrary view. To realize an AVTM, we first construct 3D gait volume sequences of training subjects, disjoint from the test subjects in the target scene. We then generate 2D gait silhouette sequences of the training subjects by projecting the 3D gait volume sequences onto the same views as the target views, and train the AVTM with gait features extracted from the 2D sequences. In addition, we extend our AVTM by incorporating a part-dependent view selection scheme (AVTM_PdVS), which divides the gait feature into several parts, and sets part-dependent destination views for transformation. Because appropriate destination views may differ for different body parts, the part-dependent destination view selection can suppress transformation errors, leading to increased recognition accuracy. Experiments using data sets collected in different settings show that the AVTM improves the accuracy of cross-view matching and that the AVTM_PdVS further improves the accuracy in many cases, in particular, verification scenarios. PMID:25423652

Muramatsu, Daigo; Shiraishi, Akira; Makihara, Yasushi; Uddin, Md Zasim; Yagi, Yasushi

2015-01-01

338

Static and dynamic optimization solutions for gait are practically equivalent  

Microsoft Academic Search

The proposition that dynamic optimization provides better estimates of muscle forces during gait than static optimization is examined by comparing a dynamic solution with two static solutions. A 23-degree-of-freedom musculoskeletal model actuated by 54 Hill-type musculotendon units was used to simulate one cycle of normal gait. The dynamic problem was to find the muscle excitations which minimized metabolic energy per

Frank C. Anderson; Marcus G. Pandy

2001-01-01

339

Tracking Polar Bears  

USGS Multimedia Gallery

Movements of 9 satellite-collared adult female polar bears were tracked in February, 2010 by satellite telemetry. Bears were collared in 2007, 2008, and 2009 on the spring-time sea ice of the southern Beaufort Sea or on the autumn pack ice in 2009. Polar bear satellite telemetry data are shown with ...

340

Grizzly bears and forestry  

Microsoft Academic Search

Today's growing demand for timber is increasing road development in once roadless forest ecosystems. Roads create both local changes in plant communities and landscape-level changes in forest connectivity. Roads also increase human access, which can be detrimental to species such as grizzly bears. Because most grizzly bear mortalities occur near roads, we examined grizzly bear attractants near roads, which could

C. L. Roever; M. S. Boyce; G. B. Stenhouse

2008-01-01

341

1-Way Bearing  

NASA Technical Reports Server (NTRS)

A one-way bearing is provided having sprags and rolling bearings both disposed between an inner and an outer race. The sprags may comprise three-dimensional sprags for preventing rotation in a non-preferential direction. The roll- ing bearings may comprise thrust rollers for transmitting axial, tilt, and radial loads between the inner and outer races.

Vranish, John M. (Inventor)

2003-01-01

342

Automatic identification of gait events using an instrumented sock  

PubMed Central

Background Textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait. Methods We investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal. Results Our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability. Conclusions This study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance. PMID:21619570

2011-01-01

343

Gait patterns in hemiplegic patients with equinus foot deformity.  

PubMed

Equinus deformity of the foot is a common feature of hemiplegia, which impairs the gait pattern of patients. The aim of the present study was to explore the role of ankle-foot deformity in gait impairment. A hierarchical cluster analysis was used to classify the gait patterns of 49 chronic hemiplegic patients with equinus deformity of the foot, based on temporal-distance parameters and joint kinematic measures obtained by an innovative protocol for motion assessment in the sagittal, frontal, and transverse planes, synthesized by parametrical analysis. Cluster analysis identified five subgroups of patients with homogenous levels of dysfunction during gait. Specific joint kinematic abnormalities were found, according to the speed of progression in each cluster. Patients with faster walking were those with less ankle-foot complex impairment or with reduced range of motion of ankle-foot complex, that is with a stiff ankle-foot complex. Slow walking was typical of patients with ankle-foot complex instability (i.e., larger motion in all the planes), severe equinus and hip internal rotation pattern, and patients with hip external rotation pattern. Clustering of gait patterns in these patients is helpful for a better understanding of dysfunction during gait and delivering more targeted treatment. PMID:24967417

Manca, M; Ferraresi, G; Cosma, M; Cavazzuti, L; Morelli, M; Benedetti, M G

2014-01-01

344

Gait Patterns in Hemiplegic Patients with Equinus Foot Deformity  

PubMed Central

Equinus deformity of the foot is a common feature of hemiplegia, which impairs the gait pattern of patients. The aim of the present study was to explore the role of ankle-foot deformity in gait impairment. A hierarchical cluster analysis was used to classify the gait patterns of 49 chronic hemiplegic patients with equinus deformity of the foot, based on temporal-distance parameters and joint kinematic measures obtained by an innovative protocol for motion assessment in the sagittal, frontal, and transverse planes, synthesized by parametrical analysis. Cluster analysis identified five subgroups of patients with homogenous levels of dysfunction during gait. Specific joint kinematic abnormalities were found, according to the speed of progression in each cluster. Patients with faster walking were those with less ankle-foot complex impairment or with reduced range of motion of ankle-foot complex, that is with a stiff ankle-foot complex. Slow walking was typical of patients with ankle-foot complex instability (i.e., larger motion in all the planes), severe equinus and hip internal rotation pattern, and patients with hip external rotation pattern. Clustering of gait patterns in these patients is helpful for a better understanding of dysfunction during gait and delivering more targeted treatment. PMID:24967417

Manca, M.; Ferraresi, G.; Cosma, M.; Cavazzuti, L.; Morelli, M.; Benedetti, M. G.

2014-01-01

345

Influence of unilateral weight on bilateral cyclograms  

NASA Astrophysics Data System (ADS)

The paper presents the results of gait parameters as a function of unilateral weight. The object of the research was a woman walking on a stationary surface and carrying in his hand weights from 0 to 15 kg. Her movement was recorded by 6 cameras recording the location of 34 markers placed at appropriate points in the body. 3D reconstruction was performed for each of the reflecting markers. Tested signals were changes in the value the joint angles of ankle, knee and hip. On the basis of about 6 cycles of movement of each load, a model for the average gait cycle was developed. The result of the experiments are graphs of changes the joint angles as a function of time, bilateral cyclograms, synchronized bilateral cyclograms and regression lines. The conclusion of the study is to determine how one-sided load affects gait asymmetry. Simple and easy to interpret method of presentation of results were also shown. Studies were conducted using VICON system.

Pellicer Costa, Juan José; Dusza, Jacek J.

2014-11-01

346

A Novel HMM Distributed Classifier for the Detection of Gait Phases by Means of a Wearable Inertial Sensor Network  

PubMed Central

In this work, we decided to apply a hierarchical weighted decision, proposed and used in other research fields, for the recognition of gait phases. The developed and validated novel distributed classifier is based on hierarchical weighted decision from outputs of scalar Hidden Markov Models (HMM) applied to angular velocities of foot, shank, and thigh. The angular velocities of ten healthy subjects were acquired via three uni-axial gyroscopes embedded in inertial measurement units (IMUs) during one walking task, repeated three times, on a treadmill. After validating the novel distributed classifier and scalar and vectorial classifiers-already proposed in the literature, with a cross-validation, classifiers were compared for sensitivity, specificity, and computational load for all combinations of the three targeted anatomical segments. Moreover, the performance of the novel distributed classifier in the estimation of gait variability in terms of mean time and coefficient of variation was evaluated. The highest values of specificity and sensitivity (>0.98) for the three classifiers examined here were obtained when the angular velocity of the foot was processed. Distributed and vectorial classifiers reached acceptable values (>0.95) when the angular velocity of shank and thigh were analyzed. Distributed and scalar classifiers showed values of computational load about 100 times lower than the one obtained with the vectorial classifier. In addition, distributed classifiers showed an excellent reliability for the evaluation of mean time and a good/excellent reliability for the coefficient of variation. In conclusion, due to the better performance and the small value of computational load, the here proposed novel distributed classifier can be implemented in the real-time application of gait phases recognition, such as to evaluate gait variability in patients or to control active orthoses for the recovery of mobility of lower limb joints. PMID:25184488

Taborri, Juri; Rossi, Stefano; Palermo, Eduardo; Patanè, Fabrizio; Cappa, Paolo

2014-01-01

347

A novel HMM distributed classifier for the detection of gait phases by means of a wearable inertial sensor network.  

PubMed

In this work, we decided to apply a hierarchical weighted decision, proposed and used in other research fields, for the recognition of gait phases. The developed and validated novel distributed classifier is based on hierarchical weighted decision from outputs of scalar Hidden Markov Models (HMM) applied to angular velocities of foot, shank, and thigh. The angular velocities of ten healthy subjects were acquired via three uni-axial gyroscopes embedded in inertial measurement units (IMUs) during one walking task, repeated three times, on a treadmill. After validating the novel distributed classifier and scalar and vectorial classifiers-already proposed in the literature, with a cross-validation, classifiers were compared for sensitivity, specificity, and computational load for all combinations of the three targeted anatomical segments. Moreover, the performance of the novel distributed classifier in the estimation of gait variability in terms of mean time and coefficient of variation was evaluated. The highest values of specificity and sensitivity (>0.98) for the three classifiers examined here were obtained when the angular velocity of the foot was processed. Distributed and vectorial classifiers reached acceptable values (>0.95) when the angular velocity of shank and thigh were analyzed. Distributed and scalar classifiers showed values of computational load about 100 times lower than the one obtained with the vectorial classifier. In addition, distributed classifiers showed an excellent reliability for the evaluation of mean time and a good/excellent reliability for the coefficient of variation. In conclusion, due to the better performance and the small value of computational load, the here proposed novel distributed classifier can be implemented in the real-time application of gait phases recognition, such as to evaluate gait variability in patients or to control active orthoses for the recovery of mobility of lower limb joints. PMID:25184488

Taborri, Juri; Rossi, Stefano; Palermo, Eduardo; Patanè, Fabrizio; Cappa, Paolo

2014-01-01

348

A floor sensor system for gait recognition Lee Middleton, Alex A. Buss, Alex I. Bazin, and Mark S. Nixon,  

E-print Network

. Formally, gait is the pattern or action of an individuals motion on foot. In gait recognition the entire- eases such as Diabetic Polyneuropathy. Reilly et. al.[11] built a system to measure gait based

349

Weight set  

NSDL National Science Digital Library

Your skin covers and protects your body. Your skin can also detect pressure and weight. You can tell that a one gram weight feels lighter than a one kilogram weight because the receptors on your skin detect more pressure from a one kilogram weight compared to a one gram weight.

N/A N/A (None; )

2005-12-11

350

Quantitative Gait Analysis Detects Significant Differences in Movement between Osteoarthritic and Nonosteoarthritic Guinea Pig Strains before and after Treatment with Flunixin Meglumine  

PubMed Central

A computer-aided gait analysis system was used to contrast two guinea pig strains with differing propensity for osteoarthritis (OA), with/without administration of a nonsteroidal anti-inflammatory drug. Walking speed and static/dynamic gait parameters were determined at baseline. Flunixin meglumine was given and animals were evaluated 4, 24, and 72 hours after treatment. Body weight was compared using unpaired t-tests. Knee joints were histologically evaluated using species-specific criteria; indices were analyzed using one-way ANOVA, Kruskal-Wallis test, followed by Dunn's multiple comparisons. A generalized linear model followed by Tukey's posttests juxtaposed gait parameters; walking speed was a covariate for other outcome measures. Body weight was not different between strains; OA-prone animals demonstrated more progressive chondropathy. At baseline, OA-prone animals had slower walking speeds, narrower hind limb bases of support, shorter stride lengths, and slower limb swing speeds relative to OA-resistant animals. These differences were not detected 4 or 24 hours after treatment. By 72 hours, OA-prone animals had returned to baseline values. These findings indicate a distinct voluntary gait pattern in a rodent model of bilateral primary OA, modification of which may allow rapid screening of novel therapies. Flunixin meglumine temporarily permitted OA-prone animals to move in a manner that was analogous to OA-resistant animals. PMID:24963402

Santangelo, K. S.; Kaeding, A. C.; Baker, S. A.; Bertone, A. L.

2014-01-01

351

The effect of the 'Gait keeper' mutation in the DMRT3 gene on gaiting ability in Icelandic horses.  

PubMed

A nonsense mutation in DMRT3 ('Gait keeper' mutation) has a predominant effect on gaiting ability in horses, being permissive for the ability to perform lateral gaits and having a favourable effect on speed capacity in trot. The DMRT3 mutant allele (A) has been found in high frequency in gaited breeds and breeds bred for harness racing, while other horse breeds were homozygous for the wild-type allele (C). The aim of this study was to evaluate further the effect of the DMRT3 nonsense mutation on the gait quality and speed capacity in the multigaited Icelandic horse and demonstrate how the frequencies of the A- and C- alleles have changed in the Icelandic horse population in recent decades. It was confirmed that homozygosity for the DMRT3 nonsense mutation relates to the ability to pace. It further had a favourable effect on scores in breeding field tests for the lateral gait tölt, demonstrated by better beat quality, speed capacity and suppleness. Horses with the CA genotype had on the other hand significantly higher scores for walk, trot, canter and gallop, and they performed better beat and suspension in trot and gallop. These results indicate that the AA genotype reinforces the coordination of ipsilateral legs, with the subsequent negative effect on the synchronized movement of diagonal legs compared with the CA genotype. The frequency of the A-allele has increased in recent decades with a corresponding decrease in the frequency of the C-allele. The estimated frequency of the A-allele in the Icelandic horse population in 2012 was 0.94. Selective breeding for lateral gaits in the Icelandic horse population has apparently altered the frequency of DMRT3 genotypes with a predicted loss of the C-allele in relatively few years. The results have practical implications for breeding and training of Icelandic horses and other gaited horse breeds. PMID:25073639

Kristjansson, T; Bjornsdottir, S; Sigurdsson, A; Andersson, L S; Lindgren, G; Helyar, S J; Klonowski, A M; Arnason, T

2014-12-01

352

Gait analysis and the cumulative gait index (CGI): Translational tools to assess impairments exhibited by rats with olivocerebellar ataxia.  

PubMed

Deviations from 'normal' locomotion exhibited by humans and laboratory animals may be determined using automated systems that capture both temporal and spatial gait parameters. Although many measures generated by these systems are unrelated and independent, some may be related and dependent, representing redundant assessments of function. To investigate this possibility, a treadmill-based system was used to capture gait parameters from normal and ataxic rats, and a multivariate analysis was conducted to determine deviations from normal. Rats were trained on the treadmill at two speeds, and gait parameters were generated prior to and following lesions of the olivocerebellar pathway. Control (non-lesioned) animals exhibited stable hindlimb gait parameters across assessments at each speed. Lesioned animals exhibited alterations in multiple hindlimb gait parameters, characterized by significant increases in stride frequency, braking duration, stance width, step angle, and paw angle and decreases in stride, stance, swing and propulsion durations, stride length and paw area. A principal component analysis of initial hindlimb measures indicated three uncorrelated factors mediating performance, termed Rhythmicity, Thrust and Contact. Deviation in the performance of each animal from the group mean was determined for each factor and values summed to yield the cumulative gait index (CGI), a single value reflecting variation within the group. The CGI for lesioned animals increased 2.3-fold relative to unlesioned animals. This study characterizes gait alterations in laboratory rats rendered ataxic by destruction of the climbing fiber pathway innervating Purkinje cells and demonstrates that a single index can be used to describe overall gait impairments. PMID:25116252

Lambert, C S; Philpot, R M; Engberg, M E; Johns, B E; Kim, S H; Wecker, L

2014-11-01

353

Cryogenic Hybrid Magnetic Bearing  

NASA Technical Reports Server (NTRS)

Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

1994-01-01

354

Extraction of human gait signatures: an inverse kinematic approach using Groebner basis theory applied to gait cycle analysis  

NASA Astrophysics Data System (ADS)

This research highlights the results obtained from applying the method of inverse kinematics, using Groebner basis theory, to the human gait cycle to extract and identify lower extremity gait signatures. The increased threat from suicide bombers and the force protection issues of today have motivated a team at Air Force Institute of Technology (AFIT) to research pattern recognition in the human gait cycle. The purpose of this research is to identify gait signatures of human subjects and distinguish between subjects carrying a load to those subjects without a load. These signatures were investigated via a model of the lower extremities based on motion capture observations, in particular, foot placement and the joint angles for subjects affected by carrying extra load on the body. The human gait cycle was captured and analyzed using a developed toolkit consisting of an inverse kinematic motion model of the lower extremity and a graphical user interface. Hip, knee, and ankle angles were analyzed to identify gait angle variance and range of motion. Female subjects exhibited the most knee angle variance and produced a proportional correlation between knee flexion and load carriage.

Barki, Anum; Kendricks, Kimberly; Tuttle, Ronald F.; Bunker, David J.; Borel, Christoph C.

2013-05-01

355

Wire Weight  

USGS Multimedia Gallery

Wire weight is lowered to water surface to measure stage at a site. Levels are made to the wire weights elevation from known benchmarks to ensure correct readings. This wire weight is located along the Missouri River in Bismarck, ND....

356

Differences in cortical activation between observing one's own gait and the gait of others: a functional near-infrared spectroscopy study.  

PubMed

Using functional near-infrared spectroscopy, we investigated cortical activation while participants observed their own gait and the gait of others. Further, we compared the vividness of motor imagery induced by observing one's own and the gait of others. Participants were instructed to perform a gait observation task. The task had two conditions: observing video clips of one's own walking and observing video clips of other individuals walking. After observing the videos, the participants were asked to evaluate the vividness of the mental image of the observed gait on a visual analog scale. When observing one's own gait, the right dorsal premotor cortex and the superior parietal lobule were activated, whereas when observing the gait of others, the left inferior parietal lobule was activated. Observing one's own gait induced imagery that was significantly more vivid than that induced when viewing the gait of others. We suggest that observing one's own gait generates a representation of one's own body in the brain and induces more vivid gait imagery. PMID:25674903

Fuchigami, Takeshi; Morioka, Shu

2015-03-01

357

Comparison of gait velocity and center of mass during square and semicircular turning gaits between groups of elderly people with differing visual acuity  

PubMed Central

[Purpose] The purpose of this study was to investigate gait velocity and center of mass (COM) during square and semicircular turning gaits between two groups of elderly people with differing visual acuity. [Subjects] Twenty elderly Korean women who could walk independently and who lived in the community were recruited. [Methods] We measured gait velocity and COM using an accelerometer during two different turning gaits. [Results] The velocity during square and semicircular turning gaits of participants with good binocular visual acuity (GBVA) was significantly higher than that of participants with poor binocular visual acuity (PBVA). The COM during square and semicircular turning gaits of the GBVA group was significantly decreased compared with that of the PBVA group. [Conclusion] These findings suggest that visual acuity affects velocity and COM during square and semicircular turning gaits of elderly people. PMID:25729174

Shin, Sun-shil; An, Duk-hyun; Yoo, Won-gyu

2015-01-01

358

Comparison of gait velocity and center of mass during square and semicircular turning gaits between groups of elderly people with differing visual acuity.  

PubMed

[Purpose] The purpose of this study was to investigate gait velocity and center of mass (COM) during square and semicircular turning gaits between two groups of elderly people with differing visual acuity. [Subjects] Twenty elderly Korean women who could walk independently and who lived in the community were recruited. [Methods] We measured gait velocity and COM using an accelerometer during two different turning gaits. [Results] The velocity during square and semicircular turning gaits of participants with good binocular visual acuity (GBVA) was significantly higher than that of participants with poor binocular visual acuity (PBVA). The COM during square and semicircular turning gaits of the GBVA group was significantly decreased compared with that of the PBVA group. [Conclusion] These findings suggest that visual acuity affects velocity and COM during square and semicircular turning gaits of elderly people. PMID:25729174

Shin, Sun-Shil; An, Duk-Hyun; Yoo, Won-Gyu

2015-02-01

359

Direct Comparison of Measured and Calculated Total Knee Replacement Force Envelopes during Walking in the Presence of Normal and Abnormal Gait Patterns  

PubMed Central

Knee joint forces measured from instrumented implants provide important information for testing the validity of computational models that predict knee joint forces. The purpose of this study was to validate a parametric numerical model for predicting knee joint contact forces against measurements from four subjects with instrumented TKRs during the stance phase of gait. Model sensitivity to abnormal gait patterns was also investigated. The results demonstrated good agreement for three subjects with relatively normal gait patterns, where the difference between the mean measured and calculated forces ranged from 0.05 to 0.45 body weights, and the envelopes of measured and calculated forces (from three walking trials) overlapped. The fourth subject, who had a “quadriceps avoidance” external moment pattern, initially had little overlap between the measured and calculated force envelopes. When additional constraints were added, tailored to the subject’s gait pattern, the model predictions improved to complete force envelope overlap. Coefficient of multiple determination analysis indicated that the shape of the measured and calculated force waveforms were similar for all subjects (adjusted coefficient of multiple correlation values between 0.88 and 0.92). The parametric model was accurate in predicting both the magnitude and waveform of the contact force, and the accuracy of model predictions was affected by deviations from normal gait patterns. Equally important, the envelope of forces generated by the range of solutions substantially overlapped with the corresponding measured envelope from multiple gait trials for a given subject, suggesting that the variable strategic processes of in vivo force generation are covered by the solution range of this parametric model. PMID:22284431

Lundberg, Hannah J.; Foucher, Kharma C.; Andriacchi, Thomas P.; Wimmer, Markus A.

2012-01-01

360

Gait patterns in twins with cerebral palsy: similarities and development over time after multilevel surgery.  

PubMed

To examine gait patterns and gait quality, 7 twins with cerebral palsy were measured preoperatively and after surgical intervention. The aim was to study differences and/or similarities in gait between twins, the influence of personal characteristics and birth conditions, and to describe the development of gait over time after single event multilevel surgery. A standardized clinical exam and a three-dimensional gait analysis were performed. Gait patterns were classified according to Sutherland and Davids, and the Gillette Gait Index was calculated as a global measure of the gait impairment. Next to subject characteristics at time of first measurement, and at time of birth, birth conditions were collected. Gait patterns were determined as crouch gait in 13 legs, as stiff gait in 6 legs and as jump gait in 8 legs. One leg showed a normal gait pattern. The knee flexion-extension angle correlated most constant with the knee flexion-extension angle of the contralateral leg (range 0.91-0.99). Correlations with the legs of the sibling showed variable correlations (range 0.44-0.99); with all other legs medium to high correlations of 0.73-0.91 were found. The Gillette Gait Index was found to initially decrease after surgical intervention. Similar correlations were found between twins or between legs for the gait pattern expressed by the knee flexion-extension angle, and the Gillette Gait Index improved after surgery. It seems that gait quality in twins with cerebral palsy is characterized predominantly by the traumatic disorder: genetic dispositions and personal characteristics only play a negligible role. PMID:23475009

van Drongelen, Stefan; Dreher, Thomas; Heitzmann, Daniel W W; Wolf, Sebastian I

2013-05-01

361

Muscle contributions to vertical and fore-aft accelerations are altered in subjects with crouch gait  

PubMed Central

The goals of this study were to determine if the muscle contributions to vertical and fore-aft acceleration of the mass center differ between crouch gait and unimpaired gait and if these muscle contributions change with crouch severity. Examining muscle contributions to mass center acceleration provides insight into the roles of individual muscles during gait and can provide guidance for treatment planning. We calculated vertical and fore-aft accelerations using musculoskeletal simulations of typically-developing children and children with cerebral palsy and crouch gait. Analysis of these simulations revealed that during unimpaired gait the quadriceps produce large upward and backward accelerations during early stance, whereas the ankle plantarflexors produce large upward and forward accelerations later in stance. In contrast, during crouch gait, the quadriceps and ankle plantarflexors produce large, opposing fore-aft accelerations throughout stance. The quadriceps force required to accelerate the mass center upward was significantly larger in crouch gait than in unimpaired gait and increased with crouch severity. The gluteus medius accelerated the mass center upward during midstance in unimpaired gait; however, during crouch gait the upward acceleration produced by the gluteus medius was significantly reduced. During unimpaired gait the quadriceps and ankle plantarflexors accelerate the mass center at different times, efficiently modulating fore-aft accelerations. However, during crouch gait, the quadriceps and ankle plantarflexors produce fore-aft accelerations at the same time and the opposing fore-aft accelerations generated by these muscles contribute to the inefficiency of crouch gait. PMID:23200083

Steele, Katherine M.; Seth, Ajay; Hicks, Jennifer L.; Schwartz, Michael H.; Delp, Scott L.

2012-01-01

362

Prediction of gait recovery in spinal cord injured individuals trained with robotic gait orthosis  

PubMed Central

Background Motor impairment is a major consequence of spinal cord injury (SCI). Earlier studies have shown that robotic gait orthosis (e.g., Lokomat) can improve an SCI individual’s walking capacity. However, little is known about the differential responses among different individuals with SCI. The present longitudinal study sought to characterize the distinct recovery patterns of gait impairment for SCI subjects receiving Lokomat training, and to identify significant predictors for these patterns. Methods Forty SCI subjects with spastic hypertonia at their ankles were randomly allocated to either control or intervention groups. Subjects in the intervention group participated in twelve 1-hour Lokomat trainings over one month, while control subjects received no interventions. Walking capacity was evaluated in terms of walking speed, functional mobility, and endurance four times, i.e. baseline, 1, 2, and 4 weeks after training, using the 10-Meter-Walking, Timed-Up-and-Go, and 6-Minute-Walking tests. Growth Mixture Modeling, an analytical framework for stratifying subjects based on longitudinal changes, was used to classify subjects, based on their gait impairment recovery patterns, and to identify the effects of Lokomat training on these improvements. Results Two recovery classes (low and high walking capacity) were identified for each clinical evaluation from both the control and intervention groups. Subjects with initial high walking capacity (i.e. shorter Timed-Up-and-Go time, higher 10-Meter-Walking speed and longer 6-Minute-Walking distance) displayed significant improvements in speed and functional mobility (0.033 m/s/week and–0.41 s/week respectively); however no significant change in endurance was observed. Subjects with low walking capacity exhibited no significant improvement. The membership in these two classes—and thus prediction of the subject’s gait improvement trajectory over time—could be determined by the subject’s maximum voluntary torque at the ankle under both plantar-and dorsi-flexion contractions determined prior to any training. Conclusion Our findings demonstrate that subjects responded to Lokomat training non-uniformly, and should potentially be grouped based on their likely recovery patterns using objective criteria. Further, we found that the subject’s ankle torque can predict whether he/she would benefit most from Lokomat training prior to the therapy. These findings are clinically significant as they can help individualize therapeutic programs that maximize patient recovery while minimizing unnecessary efforts and costs. PMID:24661681

2014-01-01

363

General tensor discriminant analysis and gabor features for gait recognition.  

PubMed

The traditional image representations are not suited to conventional classification methods, such as the linear discriminant analysis (LDA), because of the under sample problem (USP): the dimensionality of the feature space is much higher than the number of training samples. Motivated by the successes of the two dimensional LDA (2DLDA) for face recognition, we develop a general tensor discriminant analysis (GTDA) as a preprocessing step for LDA. The benefits of GTDA compared with existing preprocessing methods, e.g., principal component analysis (PCA) and 2DLDA, include 1) the USP is reduced in subsequent classification by, for example, LDA; 2) the discriminative information in the training tensors is preserved; and 3) GTDA provides stable recognition rates because the alternating projection optimization algorithm to obtain a solution of GTDA converges, while that of 2DLDA does not. We use human gait recognition to validate the proposed GTDA. The averaged gait images are utilized for gait representation. Given the popularity of Gabor function based image decompositions for image understanding and object recognition, we develop three different Gabor function based image representations: 1) the GaborD representation is the sum of Gabor filter responses over directions, 2) GaborS is the sum of Gabor filter responses over scales, and 3) GaborSD is the sum of Gabor filter responses over scales and directions. The GaborD, GaborS and GaborSD representations are applied to the problem of recognizing people from their averaged gait images.A large number of experiments were carried out to evaluate the effectiveness (recognition rate) of gait recognition based on first obtaining a Gabor, GaborD, GaborS or GaborSD image representation, then using GDTA to extract features and finally using LDA for classification. The proposed methods achieved good performance for gait recognition based on image sequences from the USF HumanID Database. Experimental comparisons are made with nine state of the art classification methods in gait recognition. PMID:17699917

Tao, Dacheng; Li, Xuelong; Wu, Xindong; Maybank, Stephen J

2007-10-01

364

Two-dimensional PCA-based human gait identification  

NASA Astrophysics Data System (ADS)

It is very necessary to recognize person through visual surveillance automatically for public security reason. Human gait based identification focus on recognizing human by his walking video automatically using computer vision and image processing approaches. As a potential biometric measure, human gait identification has attracted more and more researchers. Current human gait identification methods can be divided into two categories: model-based methods and motion-based methods. In this paper a two-Dimensional Principal Component Analysis and temporal-space analysis based human gait identification method is proposed. Using background estimation and image subtraction we can get a binary images sequence from the surveillance video. By comparing the difference of two adjacent images in the gait images sequence, we can get a difference binary images sequence. Every binary difference image indicates the body moving mode during a person walking. We use the following steps to extract the temporal-space features from the difference binary images sequence: Projecting one difference image to Y axis or X axis we can get two vectors. Project every difference image in the difference binary images sequence to Y axis or X axis difference binary images sequence we can get two matrixes. These two matrixes indicate the styles of one walking. Then Two-Dimensional Principal Component Analysis(2DPCA) is used to transform these two matrixes to two vectors while at the same time keep the maximum separability. Finally the similarity of two human gait images is calculated by the Euclidean distance of the two vectors. The performance of our methods is illustrated using the CASIA Gait Database.

Chen, Jinyan; Wu, Rongteng

2012-11-01

365

Does Anxiety Cause Freezing of Gait in Parkinson's Disease?  

PubMed Central

Individuals with Parkinson's disease (PD) commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers) and 17 PD without freezing of gait (Non-Freezers) were instructed to walk in two virtual environments: (i) across a plank that was located on the ground (LOW), (ii) across a plank above a deep pit (HIGH). Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state). Freezers reported higher levels of anxiety compared to Non-Freezers (p<0.001) and all patients reported greater levels of anxiety when walking across the HIGH plank compared to the LOW (p<0.001). Freezers experienced significantly more freezing of gait episodes (p?=?0.013) and spent a significantly greater percentage of each trial frozen (p?=?0.005) when crossing the HIGH plank. This finding was even more pronounced when comparing Freezers in their OFF state. Freezers also had greater step length variability in the HIGH compared to the LOW condition, while the step length variability in Non-Freezers did not change. In conclusion, this was the first study to directly compare freezing of gait in anxious and non-anxious situations. These results present strong evidence that anxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD. PMID:25250691

Ehgoetz Martens, Kaylena A.; Ellard, Colin G.; Almeida, Quincy J.

2014-01-01

366

Numerical limit analysis solutions for the bearing capacity factor N ?  

Microsoft Academic Search

Numerical limit analyses are applied to evaluate the self-weight bearing capacity factor for a rigid surface footing with a smooth or rough interface. To isolate the effect of the self-weight on the bearing capacity, the soil is modeled as a cohesionless frictional Mohr–Coulomb material. Assuming an associated flow rule, the true collapse load is bracketed to within 3.42% by computing

M. Hjiaj; A. V. Lyamin; S. W. Sloan

2005-01-01

367

Positive force feedback in bouncing gaits?  

PubMed Central

During bouncing gaits (running, hopping, trotting), passive compliant structures (e.g. tendons, ligaments) store and release part of the stride energy. Here, active muscles must provide the required force to withstand the developing tendon strain and to compensate for the inevitable energy losses. This requires an appropriate control of muscle activation. In this study, for hopping, the potential involvement of afferent information from muscle receptors (muscle spindles, Golgi tendon organs) is investigated using a two-segment leg model with one extensor muscle. It is found that: (i) positive feedbacks of muscle-fibre length and muscle force can result in periodic bouncing; (ii) positive force feedback (F+) stabilizes bouncing patterns within a large range of stride energies (maximum hopping height of 16.3 cm, almost twofold higher than the length feedback); and (iii) when employing this reflex scheme, for moderate hopping heights (up to 8.8 cm), an overall elastic leg behaviour is predicted (hopping frequency of 1.4-3 Hz, leg stiffness of 9-27 kN m(-1)). Furthermore, F+ could stabilize running. It is suggested that, during the stance phase of bouncing tasks, the reflex-generated motor control based on feedbacks might be an efficient and reliable alternative to central motor commands. PMID:14561282

Geyer, Hartmut; Seyfarth, Andre; Blickhan, Reinhard

2003-01-01

368

Bearings: Technology and needs  

NASA Technical Reports Server (NTRS)

A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed.

Anderson, W. J.

1982-01-01

369

Effect of explicit visual feedback distortion on human gait  

PubMed Central

Background Gait rehabilitation often utilizes correction of stepping movements, and visual feedback is one of the interactive forms that can be used for rehabilitation. We presented a paradigm called visual feedback distortion in which we manipulated the visual representation of step length. Our previous work showed that an implicit distortion of visual feedback of step length entails unintentional modulations in the subjects’ gait spatial pattern. Even in the presence of cognitive load through a distraction task, distortion of visual feedback still induced modulation of gait step length. In the current study, subjects were aware of the imposed distortion of visual feedback and they were instructed to maintain their natural gait symmetric pattern during trials. We then studied whether such an explicit “visual feedback distortion” would still influence gait spatial pattern. Methods Nine healthy subjects participated in the treadmill walking trial. The step length was defined as the distance between each foot. The on-line visual feedback showing right and left step length information as bar graphs was displayed on a computer screen. When distorting the visual feedback, the height of the bar for only one side was manipulated, so that subjects perceived their step length as being asymmetric. Actual step lengths were measured during trial and analyzed to see the effects of visual feedback distortion. Results Our results showed that a gradual distortion of visual feedback systematically modulated gait step length away from symmetry even at the expense of an opposing apparent task goal. It was also observed that the amount of induced gait modulation was reduced during the explicit condition compared to the implicit condition where subjects were not aware of distortion. Conclusions Our study demonstrated that although the visual feedback display used in this study did not alter visual space or evoke illusions of motion, perturbation of visual information about subjects’ movement can cause unintentional motor functions. This suggests that the effect of visual feedback distortion is spontaneous and a gait training involving the visual distortion paradigm may provide an effective way to help subjects correct gait patterns by driving implicit motor functions, thereby bringing benefits to rehabilitation. PMID:24775424

2014-01-01

370

A comparative collision-based analysis of human gait  

PubMed Central

This study compares human walking and running, and places them within the context of other mammalian gaits. We use a collision-based approach to analyse the fundamental dynamics of the centre of mass (CoM) according to three angles derived from the instantaneous force and velocity vectors. These dimensionless angles permit comparisons across gait, species and size. The collision angle ?, which is equivalent to the dimensionless mechanical cost of transport CoTmech, is found to be three times greater during running than walking of humans. This threefold difference is consistent with previous studies of walking versus trotting of quadrupeds, albeit tends to be greater in the gaits of humans and hopping bipeds than in quadrupeds. Plotting the collision angle ? together with the angles of the CoM force vector ? and velocity vector ? results in the functional grouping of bipedal and quadrupedal gaits according to their CoM dynamics—walking, galloping and ambling are distinguished as separate gaits that employ collision reduction, whereas trotting, running and hopping employ little collision reduction and represent more of a continuum that is influenced by dimensionless speed. Comparable with quadrupedal mammals, collision fraction (the ratio of actual to potential collision) is 0.51 during walking and 0.89 during running, indicating substantial collision reduction during walking, but not running, of humans. PMID:24089334

Lee, David V.; Comanescu, Tudor N.; Butcher, Michael T.; Bertram, John E. A.

2013-01-01

371

Secure and Privacy Enhanced Gait Authentication on Smart Phone  

PubMed Central

Smart environments established by the development of mobile technology have brought vast benefits to human being. However, authentication mechanisms on portable smart devices, particularly conventional biometric based approaches, still remain security and privacy concerns. These traditional systems are mostly based on pattern recognition and machine learning algorithms, wherein original biometric templates or extracted features are stored under unconcealed form for performing matching with a new biometric sample in the authentication phase. In this paper, we propose a novel gait based authentication using biometric cryptosystem to enhance the system security and user privacy on the smart phone. Extracted gait features are merely used to biometrically encrypt a cryptographic key which is acted as the authentication factor. Gait signals are acquired by using an inertial sensor named accelerometer in the mobile device and error correcting codes are adopted to deal with the natural variation of gait measurements. We evaluate our proposed system on a dataset consisting of gait samples of 34 volunteers. We achieved the lowest false acceptance rate (FAR) and false rejection rate (FRR) of 3.92% and 11.76%, respectively, in terms of key length of 50 bits. PMID:24955403

Choi, Deokjai

2014-01-01

372

Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis  

NASA Technical Reports Server (NTRS)

Amyotrophic lateral sclerosis (ALS) is a disorder marked by loss of motoneurons. We hypothesized that subjects with ALS would have an altered gait rhythm, with an increase in both the magnitude of the stride-to-stride fluctuations and perturbations in the fluctuation dynamics. To test for this locomotor instability, we quantitatively compared the gait rhythm of subjects with ALS with that of normal controls and with that of subjects with Parkinson's disease (PD) and Huntington's disease (HD), pathologies of the basal ganglia. Subjects walked for 5 min at their usual pace wearing an ankle-worn recorder that enabled determination of the duration of each stride and of stride-to-stride fluctuations. We found that the gait of patients with ALS is less steady and more temporally disorganized compared with that of healthy controls. In addition, advanced ALS, HD, and PD were associated with certain common, as well as apparently distinct, features of altered stride dynamics. Thus stride-to-stride control of gait rhythm is apparently compromised with ALS. Moreover, a matrix of markers based on gait dynamics may be useful in characterizing certain pathologies of motor control and, possibly, in quantitatively monitoring disease progression and evaluating therapeutic interventions.

Hausdorff, J. M.; Lertratanakul, A.; Cudkowicz, M. E.; Peterson, A. L.; Kaliton, D.; Goldberger, A. L.

2000-01-01

373

Secure and privacy enhanced gait authentication on smart phone.  

PubMed

Smart environments established by the development of mobile technology have brought vast benefits to human being. However, authentication mechanisms on portable smart devices, particularly conventional biometric based approaches, still remain security and privacy concerns. These traditional systems are mostly based on pattern recognition and machine learning algorithms, wherein original biometric templates or extracted features are stored under unconcealed form for performing matching with a new biometric sample in the authentication phase. In this paper, we propose a novel gait based authentication using biometric cryptosystem to enhance the system security and user privacy on the smart phone. Extracted gait features are merely used to biometrically encrypt a cryptographic key which is acted as the authentication factor. Gait signals are acquired by using an inertial sensor named accelerometer in the mobile device and error correcting codes are adopted to deal with the natural variation of gait measurements. We evaluate our proposed system on a dataset consisting of gait samples of 34 volunteers. We achieved the lowest false acceptance rate (FAR) and false rejection rate (FRR) of 3.92% and 11.76%, respectively, in terms of key length of 50 bits. PMID:24955403

Hoang, Thang; Choi, Deokjai

2014-01-01

374

The Incredible Water Bear  

NSDL National Science Digital Library

This image-rich Micscape Magazine article explores how water bears can be found almost everywhere yet are still unknown to almost everybody, why there are relatively few light microscope photographs of water bears in the literature and on the Web, and how light microscopy can outperform scanning electron microscopy when viewing these animals. It includes a list of historical references, early sketches, and colorful images of water bears, also known as tardigrades.

Martin Mach

375

Perception of gait patterns that deviate from normal and symmetric biped locomotion.  

PubMed

This study examines the range of gait patterns that are perceived as healthy and human-like with the goal of understanding how much asymmetry is allowable in a gait pattern before other people start to notice a gait impairment. Specifically, this study explores if certain abnormal walking patterns can be dismissed as unimpaired or not uncanny. Altering gait biomechanics is generally done in the fields of prosthetics and rehabilitation, however the perception of gait is often neglected. Although a certain gait can be functional, it may not be considered as normal by observers. On the other hand, an abnormally perceived gait may be more practical or necessary in some situations, such as limping after an injury or stroke and when wearing a prosthesis. This research will help to find the balance between the form and function of gait. Gait patterns are synthetically created using a passive dynamic walker (PDW) model that allows gait patterns to be systematically changed without the confounding influence from human sensorimotor feedback during walking. This standardized method allows the perception of specific changes in gait to be studied. The PDW model was used to produce walking patterns that showed a degree of abnormality in gait cadence, knee height, step length, and swing time created by changing the foot roll-over-shape, knee damping, knee location, and leg masses. The gait patterns were shown to participants who rated them according to separate scales of impairment and uncanniness. The results indicate that some pathological and asymmetric gait patterns are perceived as unimpaired and normal. Step time and step length asymmetries less than 5%, small knee location differences, and gait cadence changes of 25% do not result in a change in perception. The results also show that the parameters of a pathologically or uncanny perceived gait can be beneficially altered by increasing other independent parameters, in some sense masking the initial pathology. PMID:25774144

Handži?, Ismet; Reed, Kyle B

2015-01-01

376

Perception of gait patterns that deviate from normal and symmetric biped locomotion  

PubMed Central

This study examines the range of gait patterns that are perceived as healthy and human-like with the goal of understanding how much asymmetry is allowable in a gait pattern before other people start to notice a gait impairment. Specifically, this study explores if certain abnormal walking patterns can be dismissed as unimpaired or not uncanny. Altering gait biomechanics is generally done in the fields of prosthetics and rehabilitation, however the perception of gait is often neglected. Although a certain gait can be functional, it may not be considered as normal by observers. On the other hand, an abnormally perceived gait may be more practical or necessary in some situations, such as limping after an injury or stroke and when wearing a prosthesis. This research will help to find the balance between the form and function of gait. Gait patterns are synthetically created using a passive dynamic walker (PDW) model that allows gait patterns to be systematically changed without the confounding influence from human sensorimotor feedback during walking. This standardized method allows the perception of specific changes in gait to be studied. The PDW model was used to produce walking patterns that showed a degree of abnormality in gait cadence, knee height, step length, and swing time created by changing the foot roll-over-shape, knee damping, knee location, and leg masses. The gait patterns were shown to participants who rated them according to separate scales of impairment and uncanniness. The results indicate that some pathological and asymmetric gait patterns are perceived as unimpaired and normal. Step time and step length asymmetries less than 5%, small knee location differences, and gait cadence changes of 25% do not result in a change in perception. The results also show that the parameters of a pathologically or uncanny perceived gait can be beneficially altered by increasing other independent parameters, in some sense masking the initial pathology. PMID:25774144

Handži?, Ismet; Reed, Kyle B.

2015-01-01

377

Bearing restoration by grinding  

NASA Technical Reports Server (NTRS)

A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

1976-01-01

378

Linear magnetic bearing  

NASA Technical Reports Server (NTRS)

A linear magnetic bearing system having electromagnetic vernier flux paths in shunt relation with permanent magnets, so that the vernier flux does not traverse the permanent magnet, is described. Novelty is believed to reside in providing a linear magnetic bearing having electromagnetic flux paths that bypass high reluctance permanent magnets. Particular novelty is believed to reside in providing a linear magnetic bearing with a pair of axially spaced elements having electromagnets for establishing vernier x and y axis control. The magnetic bearing system has possible use in connection with a long life reciprocating cryogenic refrigerator that may be used on the space shuttle.

Studer, P. A. (inventor)

1983-01-01

379

Results of using a wireless inertial measurirlg system to quantify gait motions in control subjects  

Microsoft Academic Search

Gait analysis is important for the diagnosis of many neurological diseases such as Parkinson's. The discovery and interpretation of minor gait abnormalities can aid in early diagnosis. We have used an inertial measuring system mounted on the subject's foot to provide numerical measures of a subject's gait (3-D displacements and rotations), thereby creating an automated tool intended to facilitate diagnosis

Iris Tien; Steven D. Glaser; Ruzena Bajcsy; Douglas S. Goodin; Michael J. Aminoff

2010-01-01

380

Responsiveness and predictability of gait speed and other disability measures in acute stroke  

Microsoft Academic Search

Salbach NM, Mayo NE, Higgins J, Ahmed S, Finch LE, Richards CL. Responsiveness and predictability of gait speed and other disability measures in acute stroke. Arch Phys Med Rehabil 2001;82;1204-12. Objectives: To identify the most responsive method of measuring gait speed, to estimate the responsiveness of other outcome measures, and to determine whether gait speed predicts discharge destination in acute

Nancy M. Salbach; Nancy E. Mayo; Johanne Higgins; Sara Ahmed; Lois E. Finch; Carol L. Richards

2001-01-01

381

The HumanID Gait Challenge Problem: Data Sets, Performance, and Analysis  

E-print Network

experiment to 3 percent on the hardest. All five covariates had statistically significant effects analysis of gait has been successfully applied in human clinical gait analysis [1]. With regards to gait according to the model employed: Articulated versus elastic nonrigid, with and without prior shape modeled

Sarkar, Sudeep

382

Evaluation of gait with trans-femoral prosthesis based on Riemannian distance  

Microsoft Academic Search

This paper presents a method to quantify the goodness of gait with a trans-femoral prosthesis in order to evaluate walking skill with the prosthesis and its application to its design. Advancements in the mechanism and the control method of trans-femoral prostheses have drastically improved the gait of amputees. However, realization of a natural gait has not been investigated in detail

T. Wada; Toyokazu Takeuchi; Masahiro Sekimoto; Yuuki Shiba; Suguru Arimoto

2009-01-01

383

Gait analysis in idiopathic normal pressure hydrocephalus – which parameters respond to the CSF tap test?  

Microsoft Academic Search

Objectives: Normal pressure hydrocephalus (NPH) is an often underestimated cause of hypokinetic gait disorders in the elderly. Diagnosing NPH is a complex problem, since many symptoms overlap with other neurological diseases. The purpose of the present study was to characterize the gait pattern in NPH quantitatively. Additionally, we analyzed the improvement of gait parameters following tapping of cerebrospinal fluid (CSF).Methods:

H Stolze; J. P Kuhtz-Buschbeck; H Drücke; K Jöhnk; C Diercks; S Palmié; H. M Mehdorn; M Illert; G Deuschl

2000-01-01

384

Can Gait Velocity Predict Which Older Adults Will or Will Not Fall? Danielle Hernandez1  

E-print Network

) for the maximum speed condition. Gait velocity (measured in ft/sec) is then calculated for each speed condition the constant model (intercept only model), indicating that the gait velocity for the preferred speed condition of being a faller based on mean gait velocity at a preferred speed was calculated using the following

de Lijser, Peter

385

Efficient Gait Generation using Reinforcement Josep M Porta and Enric Celaya  

E-print Network

, we decided to use a reinforcement learning algorithm to automatically adapt the gait of the robotEfficient Gait Generation using Reinforcement Learning Josep M Porta and Enric Celaya Institut de to a reinforcement signal. Results of the application of a novel reinforcement learning algorithm to the free gait

Portland State University

386

Computational Intelligence in Gait Research: A Perspective on Current Applications and Future Challenges  

Microsoft Academic Search

Our mobility is an important daily requirement so much so that any disruption to it severely degrades our perceived quality of life. Studies in gait and human movement sciences, there- fore, play a significant role in maintaining the well-being of our mobility. Current gait analysis involves numerous interdependent gait parameters that are difficult to adequately interpret due to the large

Daniel T. H. Lai; Rezaul K. Begg; Marimuthu Palaniswami

2009-01-01

387

RESEARCH ARTICLE Open Access Differences in gait characteristics between total hip,  

E-print Network

RESEARCH ARTICLE Open Access Differences in gait characteristics between total hip, knee, and ankle arthroplasty (THA), total knee arthroplasty (TKA) and total ankle arthroplasty (TAA) with a group of healthy side-to-side asymmetries in gait characteristics. Keywords: Gait, Arthroplasty, Hip, Knee, Ankle

Boyer, Edmond

388

Determination of gait patterns in children with spastic diplegic cerebral palsy using principal components  

Microsoft Academic Search

This study developed an objective graphical classification method of spastic diplegic cerebral palsy (CP) gait patterns based on principal component analysis (PCA). Gait analyses of 20 healthy and 20 spastic diplegic CP children were examined to define gait characteristics. PCA was used to reduce the dimensionality of 27 parameters (26 selected kinematics variables and age of the children) for the

Alessandra Carriero; Amy Zavatsky; Julie Stebbins; Tim Theologis; Sandra J. Shefelbine

2009-01-01

389

Gait Pattern Differences between Children with Mild Scoliosis and Children with Unilateral Cerebral Palsy  

PubMed Central

This study was conducted to investigate the effects of asymmetrical body posture alone, i.e., the effects seen in children with mild scoliosis, vs. the effects of body posture control impairment, i.e., those seen in children with unilateral cerebral palsy on gait patterns. Three-dimensional instrumented gait analysis (3DGA) was conducted in 45 children with hemiplegia and 51 children with mild scoliosis. All the children were able to walk without assistance devices. A set of 35 selected spatiotemporal gait and kinematics parameters were evaluated when subjects walked on a treadmill. A cluster analysis revealed 3 different gait patterns: a scoliotic gait pattern and 2 different hemiplegic gait patterns. The results showed that the discrepancy in gait patterns was not simply a lower limb kinematic deviation in the sagittal plane, as expected. Additional altered kinematics, such as pelvic misorientation in the coronal plane in both the stance and swing phases and inadequate stance phase hip ad/abduction, which resulted from postural pattern features, were distinguished between the 3 gait patterns. Our study provides evidence for a strong correlation between postural and gait patterns in children with unilateral cerebral palsy. Information on differences in gait patterns may be used to improve the guidelines for early therapy for children with hemiplegia before abnormal gait patterns are fully established. The gait pathology characteristic of scoliotic children is a potential new direction for treating scoliosis that complements the standard posture and walking control therapy exercises with the use of biofeedback. PMID:25089908

Domagalska-Szopa, Ma?gorzata; Szopa, Andrzej

2014-01-01

390

Longitudinal Change in Gait and Motor Function in Pre-manifest Huntington's Disease  

E-print Network

Longitudinal Change in Gait and Motor Function in Pre-manifest Huntington's Disease The purpose of this study was to examine longitudinal change in gait and motor function in pre-manifest Huntington's disease with the motor component of the Unified Huntington's Disease Rating Scale. Gait velocity decreased (p=0

391

Longitudinal Change in Gait and Motor Function in Pre-manifest Huntington's Disease  

E-print Network

Longitudinal Change in Gait and Motor Function in Pre-manifest Huntington's Disease October 11 of this study was to examine longitudinal change in gait and motor function in pre-manifest Huntington's disease with the motor component of the Unified Huntington's Disease Rating Scale. Gait velocity decreased (p=0

392

A normative sample of temporal and spatial gait parameters in children using the GAITRite ® electronic walkway  

Microsoft Academic Search

PurposeThe purpose of this study was to develop a normative sample of temporal and spatial gait parameters for children (ages 1–10 years) using the GAITRite® electronic walkway. Reliability of the GAITRite® for assessing gait in children is similar to its reliability in adults. Normative temporal and spatial gait parameters have not been published using the GAITRite® limiting clinicians and researchers

Stacey C. Dusing; Deborah E. Thorpe

2007-01-01

393

Criterion validity of 3D trunk accelerations to assess external work and power in able-bodied gait.  

PubMed

Evaluative quantification of gait disorder minimizing time-consuming and cost-intensive laboratory installations remains a challenging task in movement analysis. We examined the criterion validity of global gait mechanics assessed by trunk accelerometry. Eight female and four male volunteer subjects (mean age, 27.5 years; S.D., 5.1 years; weight, 68.7+/-11.3kg; height, 1.74+/-0.08m) without gait dysfunction participated in the study. They walked barefoot over two adjacent force-platforms at self-selected speeds. In addition to ground reaction forces, vertical, anterior-posterior and medio-lateral accelerations of the trunk were simultaneously measured by means of a light tri-axial accelerometer. Mean acceleration cycles of the trunk and the body centre of mass were calculated. Acceleration vectors were integrated twice to obtain velocity and displacement vectors of the trunk and the centre of mass, respectively. Temporal boundaries of right and left functional stance phases were defined by the two intermediate moments between maximum anterior-posterior velocity and minimal vertical displacement. Cross-correlations of the kinematics of the trunk and the centre of mass were determined. External work and corresponding symmetry indicators were computed for both methods. Centre of mass anterior-posterior displacement lagged behind the trunk by 3.5% of the gait cycle. External power correlated highly (r>0.82) between the trunk model and the centre of mass. Work correlated moderately high (r=0.77) between the two methods. Work and power asymmetry indexes correlated moderately high (r>0.64). Our findings suggest that accelerometry has the potential to assess functional kinematics and energy-related outcomes in large cohorts. PMID:16483779

Meichtry, André; Romkes, Jacqueline; Gobelet, Charles; Brunner, Reinald; Müller, Roland

2007-01-01

394

Effect of Task Specific Exercises, Gait Training, and Visual Biofeedback on Equinovarus Gait among Individuals with Stroke: Randomized Controlled Study  

PubMed Central

Background and Purpose. Equinovarus foot is a common sign after stroke. The aim of this study is to investigate the effect of task specific exercises, gait training, and visual biofeedback on correcting equinovarus gait among individuals with stroke. Subjects and Methods. Sixteen subjects with ischemic stroke were randomly assigned to two equal groups (G1 and G2). All the patients were at stage 4 of motor recovery of foot according to Chedoke-McMaster Stroke Assessment without any cognitive dysfunction. E-med pedography was used to measure contact time, as well as force underneath hind and forefoot during walking. Outcome measures were collected before randomization, one week after the last session, and four weeks later. Participants in G1 received task specific exercises, gait training, and visual biofeedback and a traditional physical therapy program was applied for participants in G2 for 8 weeks. Results. Significant improvement was observed among G1 patients (P ? 0.05) which lasts one month after therapy termination. On the other hand, there were no significant differences between measurements of the participants in G2. Between groups comparison also revealed a significant improvement in G1 with long lasting effect. Conclusion. The results of this study showed a positive long lasting effect of the task specific exercises, gait training, and visual biofeedback on equinovarus gait pattern among individuals with stroke. PMID:25538853

Khallaf, Mohamed Elsayed; Gabr, Ahmed Maher; Fayed, Eman Elsayed

2014-01-01

395

Effect of Task Specific Exercises, Gait Training, and Visual Biofeedback on Equinovarus Gait among Individuals with Stroke: Randomized Controlled Study.  

PubMed

Background and Purpose. Equinovarus foot is a common sign after stroke. The aim of this study is to investigate the effect of task specific exercises, gait training, and visual biofeedback on correcting equinovarus gait among individuals with stroke. Subjects and Methods. Sixteen subjects with ischemic stroke were randomly assigned to two equal groups (G1 and G2). All the patients were at stage 4 of motor recovery of foot according to Chedoke-McMaster Stroke Assessment without any cognitive dysfunction. E-med pedography was used to measure contact time, as well as force underneath hind and forefoot during walking. Outcome measures were collected before randomization, one week after the last session, and four weeks later. Participants in G1 received task specific exercises, gait training, and visual biofeedback and a traditional physical therapy program was applied for participants in G2 for 8 weeks. Results. Significant improvement was observed among G1 patients (P ? 0.05) which lasts one month after therapy termination. On the other hand, there were no significant differences between measurements of the participants in G2. Between groups comparison also revealed a significant improvement in G1 with long lasting effect. Conclusion. The results of this study showed a positive long lasting effect of the task specific exercises, gait training, and visual biofeedback on equinovarus gait pattern among individuals with stroke. PMID:25538853

Khallaf, Mohamed Elsayed; Gabr, Ahmed Maher; Fayed, Eman Elsayed

2014-01-01

396

Synchronized walking coordination for impact-less footpad contact of an overground gait rehabilitation system: NaTUre-gaits.  

PubMed

Due to the labor-intensiveness and the shortage of therapists in the application of most forms of manually assisted gait training in neuro-rehabilitation, robotics rehabilitation gait systems have been developed to contribute in such fields of neuro-rehabilitation. This paper presents an overground gait rehabilitation robot, which consists of a pair of robotic orthosis (RO) connected to pelvic arm (PA) and mounted on a mobile platform (MP). As the robotic orthosis (RO) is connected to pelvic arm (PA), the compensation between the two modules should be considered. Possible problems that may surface during overground walking include: 1. Ground impact problem. 2. Poor coordination to mobile platform (MP) which would cause foot drag. To reduce, if not to avoid, the ground impact and dragging of the footpad occurring during the course of overground walking with help of the device, a gait motion generation is developed and specified to adjust the gait patterns for an impactless and smooth footpad contact. The initial tests demonstrate the effectiveness and smoothness of the overground walking on the system. PMID:22275557

Wang, Ping; Low, K H; Tow, A

2011-01-01

397

Human-centered robotics applied to gait training and assessment.  

PubMed

Robot-aided gait training can increase the duration and number of training sessions while reducing the number of therapists required for each patient. However, current automated gait trainers do not adapt their movement to the patient's muscular efforts and passive musculoskeletal properties. Furthermore, robot-aided training without therapists lacks the feedback required for patient assessment. In this article, we present results from the literature and our research to provide an overview of novel human-centered strategies for robot behaviors that are patient-cooperative and support motor-function assessment. Combining robot-aided training with robot-aided assessment will likely make future gait therapy easier, more comfortable, and more efficient. Broad clinical testing is still required for proving this assumption. PMID:17123208

Riener, Robert; Lünenburger, Lars; Colombo, Gery

2006-01-01

398

Gait impairment in neurological disorders: a new technological approach.  

PubMed

Gait recovery is considered one of the main objectives of rehabilitation interventions in neurological disabilities, as restricted movement can significantly reduce an individual's ability to take part in normal activities of daily living. Locomotor training has been shown to improve gait rehabilitation. Studies have recently been published on the use of robots and other devices in patients with gait disabilities, particularly in the rehabilitation of the lower limbs. However, analysis of the recent literature reveals a relative paucity of strong methodological studies. The evidence that is available, while strong, is not yet sufficient to allow definite conclusions to be drawn regarding the efficacy of these devices. From these considerations, it is clear that validated and standardized methods need to be adopted for each of the different systems available. This would help to clarify the indications for and correct use of robotic devices in the different neurological disorders. PMID:20412722

Semprini, Roberta; Sale, Patrizio; Foti, Calogero; Fini, Massimo; Franceschini, Marco

2009-01-01

399

Extracting gait parameters from raw electronic walkway data.  

PubMed

Spatiotemporal gait parameters are very important for the detection of gait impairments and associated conditions. Current methods to measure such parameters, e.g. electronic walkways or force plates, are costly and can only be used in a laboratory. The new generation of raw data accelerometers might be a cheap and flexible alternative. We conducted a small feasibility study with 50 subjects from the KORA-Age project exploring the output of GAITRite and Actigraph GT3X. We open-sourced a package to extract and process raw data from GAITRite. The most promising location for the accelerometer seems to be at the ankle. The use of accelerometers showed to be simple and reliable, indicating that they can be used in daily life to extract gait parameters. PMID:21893789

Dias, André; Gorzelniak, Lukas; Döring, Angela; Hartvigsen, Gunnar; Horsch, Alexander

2011-01-01

400

Gait speed in Parkinson disease correlates with cholinergic degeneration  

PubMed Central

Objective: We investigated dopaminergic and cholinergic correlates of gait speed in Parkinson disease (PD) and non-PD control subjects to test the hypothesis that gait dysfunction in PD may result from multisystem degeneration. Methods: This was a cross-sectional study. Subjects with PD but without dementia (n = 125, age 65.6 ± 7.3 years) and elderly subjects without PD (n = 32, age 66.0 ± 10.6 years) underwent [11C]dihydrotetrabenazine dopaminergic and [11C]methyl-4-piperidinyl propionate acetylcholinesterase PET imaging, and cognitive and clinical testing, including an 8.5-m walk in the dopaminergic “off” state. The fifth percentile of cortical cholinergic activity in the elderly without PD was used to define normal-range activity in the subjects with PD. Results: Normal-range cortical cholinergic activity was present in 87 subjects with PD (69.6%). Analysis of covariance using gait speed as the dependent variable demonstrated a significant model (F = 6.70, p < 0.0001) with a significant group effect (F = 3.36, p = 0.037) and significant slower gait speed in the low cholinergic PD subgroup (0.97 ± 0.22 m/s) with no significant difference between the normal-range cholinergic PD subgroup (1.12 ± 0.20 m/s) and control subjects (1.17 ± 0.18 m/s). Covariate effects were significant for cognition (F = 6.58, p = 0.011), but not for striatal dopaminergic innervation, sex, or age. Conclusion: Comorbid cortical cholinergic denervation is a more robust marker of slowing of gait in PD than nigrostriatal denervation alone. Gait speed is not significantly slower than normal in subjects with PD with relatively isolated nigrostriatal denervation. PMID:24078735

Frey, Kirk A.; Studenski, Stephanie; Kotagal, Vikas; Koeppe, Robert A.; Scott, Peter J.H.; Albin, Roger L.; Müller, Martijn L.T.M.

2013-01-01

401

Subtle gait changes in patients with REM Behavior Disorder  

PubMed Central

Background Many people with REM sleep behavior disorder have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. As gait disorders are common in the synucleinopathies, early abnormalities in gait in those with REM sleep behavior disorder could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. Methods We identified 42 probable REM sleep behavior disorder subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence and stride dynamics with an automated gait analysis system. Results Cases and controls were similar in age (79.9 ± 4.7 & 80.1 ± 4.7, p= 0.74), UPDRS score (3.3 ± 5.5 & 1.9 ± 4.1, p=0.21) and Mini-Mental State Examination scores (27.2 ± 1.9 & 27.7 ± 1.6, p=0.10). A diagnosis of probable REM sleep behavior disorder was associated with decreased velocity (?7.9 cm/sec, 95%CI ?13.8 to ?2.0, p<0.01), cadence (?4.4 steps/min, 95%CI ?7.6 to ?1.3, p<0.01), and significantly increased double limb support variability (30%, 95%CI 6 – 60, p=0.01), greater stride time variability (29%, 95%CI 2 – 63, p=0.03) and swing time variability (46%, 95%CI 15 – 84, p<0.01). Conclusions Probable REM sleep behavior disorder is associated with subtle gait changes prior to overt clinical parkinsonism. Diagnosis of probable REM sleep behavior disorder supplemented by gait analysis may help as a screening tool for disorders of ?-synuclein. PMID:24130124

McDade, Eric M; Boot, Brendon P.; Christianson, Teresa JH; Pankratz, V. Shane; Boeve, Bradley F; Ferman, Tanis J.; Bieniek, Kevin; Hollman, John H; Roberts, Rosebud O; Mielke, Michelle M; Knopman, David S.; Petersen, Ronald C.

2013-01-01

402

Gait and balance in adults with Friedreich's ataxia.  

PubMed

Friedreich's ataxia (FA) is an autosomal recessive, neurodegenerative disease characterized by progressive muscle weakness and sensory loss, balance deficits, and gait ataxia. Gait and balance impairments become worse as the disease progresses, but limited research has quantitatively assessed these deficits in adults with FA. The purpose of this study was to analyze gait and balance in this population and investigate the relationship between these variables. Eight subjects with genetically confirmed FA (29.4±9.0 years) and eight healthy, matched control subjects (29.6±9.1 years) participated in this study. Spatiotemporal gait parameters were examined using the GAITRite Walkway System while balance was examined utilizing the Biodex Balance System SD and the Berg Balance Scale (BBS). The FA group exhibited approximately 50% slower gait velocity and 32% shorter step and stride lengths compared to the control group for both comfortable and fast walking (p<0.001). Further, stride length variability in the FA group was 3.4 and 2.7 times that of controls for comfortable and fast walking, respectively (p<0.01). Subjects with FA took 72% longer to complete the limits of stability (LOS) test and attained an overall directional control score that was 50% that of controls (p<0.05). Lastly, age at FA symptom onset correlated with stride length variability during fast walking (p<0.05), and BBS and LOS test scores correlated with stride length variability during both comfortable and fast walking (p<0.05). Results demonstrate that adults with FA have significantly impaired gait and balance and several measures of these impairments are correlated. PMID:25662043

Stephenson, Jeannie; Zesiewicz, Theresa; Gooch, Clifton; Wecker, Lynn; Sullivan, Kelly; Jahan, Israt; Kim, Seok Hun

2015-02-01

403

Gait planning for a quadruped robot with one faulty actuator  

NASA Astrophysics Data System (ADS)

Fault tolerance is essential for quadruped robots when they work in remote areas or hazardous environments. Many fault-tolerant gaits planning method proposed in the past decade constrained more degrees of freedom(DOFs) of a robot than necessary. Thus a novel method to realize the fault-tolerant walking is proposed. The mobility of the robot is analyzed first by using the screw theory. The result shows that the translation of the center of body(CoB) can be kept with one faulty actuator if the rotations of the body are controlled. Thus the DOFs of the robot body are divided into two parts: the translation of the CoB and the rotation of the body. The kinematic model of the whole robot is built, the algorithm is developed to actively control the body orientations at the velocity level so that the planned CoB trajectory can be realized in spite of the constraint of the faulty actuator. This gait has a similar generation sequence with the normal gait and can be applied to the robot at any position. Simulations and experiments of the fault-tolerant gait with one faulty actuator are carried out. The CoB errors and the body rotation angles are measured. Comparing to the traditional fault-tolerant gait they can be reduced by at least 50%. A fault-tolerant gait planning algorithm is presented, which not only realizes the walking of a quadruped robot with a faulty actuator, but also efficiently improves the walking performances by taking full advantage of the remaining operational actuators according to the results of the simulations and experiments.

Chen, Xianbao; Gao, Feng; Qi, Chenkun; Tian, Xinghua

2015-01-01

404

Gait status 17-26 years after selective dorsal rhizotomy.  

PubMed

The purpose of this study was to use three-dimensional gait analysis to describe the gait status of adults with spastic diplegia who underwent selective dorsal rhizotomy (SDR) in childhood. Outcome measures were the gait deviation index (GDI), non-dimensional temporal-distance parameters, and kinematics of the lower limbs. A total of 31 adults with spastic diplegia who had previously undergone SDR were eligible and participated in current study (SDR group). These participants had a median age of 26.8 years (range 21-44 years) with a mean time between surgery and assessment of 21.2±2.9 years (range 17-26 years). For comparison purposes, 43 typically developed adults also participated (CONTROL group), with a median age of 28.3 years (range 21-45 years). More than 17 years after SDR 58% of the SDR group showed improved GMFCS levels, while none of them deteriorated. The participants in the SDR group walked with a mild crouch gait, although there was a loading response, adequate swing-phase knee flexion, adequate swing-phase plantarflexion, reasonable speed and cadence. The gait status of the SDR group more than 17 years after SDR was similar to what has been reported in short-term follow-up studies, as well as our earlier 20 year follow-up study that did not include 3D gait analysis. Appropriate orthopaedic intervention was required in 61% of the study cohort. Whether the types and numbers of orthopaedic interventions are positively affected by SDR remains an open question. Further studies examining this question are warranted. In addition, long-term follow-up studies focused on other interventions would also be of clinical relevance. PMID:22050972

Langerak, Nelleke G; Tam, Nicholas; Vaughan, Christopher L; Fieggen, A Graham; Schwartz, Michael H

2012-02-01

405

ERROR COMPENSATION OF THE MAGLEV STAGE SUPPORTED BY PERMANENT MAGNET BIASED MAGNETIC BEARING  

Microsoft Academic Search

This paper provides the design of permanent magnet biased magnetic bearing and the error compensation of the maglev (magnetically levitated) stage supported by this bearing. A magnetic bearing composed of only two electromagnets needs large amount of bias current to support its own weight so that its load capacity is limited and the energy consumption becomes large. To eliminate these

Sang-Ho Lee; Jee-Uk Chang; Sang-Wook Lee; Oui-Serg Kim; Dong-Chul Han; In-Bae Chang

406

Inhibition, Executive Function, and Freezing of Gait  

PubMed Central

Background Studies suggest that freezing of gait (FoG) in people with Parkinson’s disease (PD) is associated with declines in executive function (EF). However, EF is multi-faceted, including three dissociable components: inhibiting prepotent responses, switching between task sets, and updating working memory. Objective This study investigated which aspect of EF is most strongly associated with FoG in PD. Method Three groups were studied: adults with PD (with and without FoG) and age-matched, healthy adults. All participants completed a battery of cognitive tasks previously shown to discriminate among the three EF components. Participants also completed a turning-in-place task that was scored for FoG by neurologists blind to subjects’ self-reported FoG. Results Compared to both other groups, participants with FoG showed significant performance deficits in tasks associated with inhibitory control, even after accounting for differences in disease severity, but no significant deficits in task-switching or updating working memory. Surprisingly, the strongest effect was an intermittent tendency of participants with FoG to hesitate, and thus miss the response window, on go trials in the Go-Nogo task. The FoG group also made slower responses in the conflict condition of the Stroop task. Physician-rated FoG scores were correlated both with failures to respond on go trials and with failures to inhibit responses on nogo trials in the Go-Nogo task. Conclusion These results suggest that FoG is associated with a specific inability to appropriately engage and release inhibition, rather than with a general executive deficit. PMID:24496099

Cohen, Rajal G.; Klein, Krystal A.; Nomura, Mariko; Fleming, Michael; Mancini, Martina; Giladi, Nir; Nutt, John G.; Horak, Fay B.

2014-01-01

407

Proprioceptive perturbations of stability during gait.  

PubMed

Through recent studies, the role of proprioceptors in reactions to perturbations during gait has been finally somewhat better understood. The input from spindle afferents has been investigated with tendon taps, vibration and other forms of muscle stretches, including some resembling natural perturbations (stumbling, slips, and ankle inversions). It was found that activation of spindle afferents produces short-latency response (SLR), consistent with a fast spinal pathway. These reflexes induce relatively minor activation in the stretched muscles. A central question is whether stretch reflexes can occur for stimuli that are quite remote. Thus, a new study was made to examine whether foot sole vibration is able to elicit reflex responses in upper-leg muscles, for example by conduction of vibrations throughout the whole leg. SLR responses were indeed found not only in lower- but also in upper-leg muscles. Similarly during stumbling, SLR are observed throughout the whole limb, although the primary perturbation occurs at foot level. After the SLR, much stronger activations usually occur, with latencies (85 or 120ms) well below those seen in voluntary contractions. These late responses are much more selective and presumably linked to the maintenance of stability. The role of the I(b) afferents from the Golgi tendon organs (GTO) is less clear. From animal work, it is known that these afferents are very sensitive to active muscle contraction and that